Hello,
I'm a EUW player who has been active for a long time (ever since S3). Competitively speaking I peaked at Diamond III during seasons 4 through 7. I'm writing this post because I wish to contribute with my own general feedback on both the new Runes System as a whole and on each individual rune revealed so far in order to provide constructive input to help future balancing. I apologize in advance because this is gonna be a very long post: it would have actually been a lot better if I had taken the time to review each one of the new Runes as they got progressively revealed but since I didn't bother doing so earlier I'm now left with no choice but to make one single giant post about them all. I also failed to find a general thread that would be fit for my post so I thought the best way to make sure Riot would notice it was to simply add it as a reply below the newest revealed set of Runes. I would also like to add that I'm perfectly aware the numbers are totally temporary and will likely change before the release of the new system. Nevertheless, I will still reference them a lot in order to give clues as to whether in my opinion a certain rune is looking potentially too strong or too weak. Below follows my own personal review of each rune revealed so far, let me know if my feedback can be of any help.
BERSERK: I find this to be too strong. A 60% attack speed steroid that lasts up to 10 seconds is simply too much. None of the other offense oriented Keystones provide a damage boost that is even remotey comparable to this one, let alone those have significant cooldowns too (i.e. 50 seconds for Stormlord Mandate, 180 for Hunt of the blood moon). This rune needs to be either toned down or have a significant cooldown added to it (except at that point it would feel very uncomfortable to use as it would randomly trigger even when you don't want it to). Either way, upon triggering this Rune still grants an Attack Speed bonus worth 1500 gold which is why I would simply suggest tuning its numbers down. A lot. I otherwise like the presence of a tool that allows players to invest and capitalize in sustained damage (whereas Stormlord Mandate and Hunt of the blood moon are the burst damage related alternatives).
PERXIE: The Keystone's mechanic implies it's pretty much for enchanters only. I think it's somewhat ok but at the same time kind of mediocre: what I dislike the most is that enchanters focused heavily on defense (Janna/Soraka) will make little use of the damage component of this Keystone (since damage is kind of useless on them anyway), whereas those that can exploit both effects (Lulu, Nami, others) are gonna be penalized by Perxie's internal cooldown (Nami's W can either give a bonus shield or extra damage but not both things). The rune's cooldown will in my opinion ultimately dictate how satisfying this Keystone feels to use (I will admit I haven't pictured clearly enough Perxie's return pattern just yet).
OVERHEAL: I feel this rune is a bit wasted for a Major slot because few champions can consistently use it unless it works with regular HP regen as well. Even if I have Soraka on my team I'd be forced to constantly roam to bot lane to receive my shield, not to mention since the shield scales off my total HP it becomes worth picking only if I'm a tank. I feel a few champions such as Vladimir and Mundo are gonna capitalize a lot on it while most champions shouldn't even remotely consider picking it, which feels kinda unfair and unhealthy design wise. My suggestion would be to downgrade it from Major slot and tune it down a little bit in return.
ZOMBIE WARD: The concept behind this rune is very interesting but the fact the Zombie ward is visible kinda ruins it: as a support main myself I can tell a support that is losing will make little use of this Rune because the lack of map control implies the enemy team will likely spot and kill the visible ward very soon. On the other hand, a support that is already winning usually has no problem keeping vision control around the enemy rotations with the three regular wards he gets from sightstone because of the limited area of influence the enemy has left. Either that, or what he may otherwise want is to buy pink wards to set up picks. In general I feel the only time this Rune can be useful is when map control is kind of even, which also implies Junlgers are likely better candidates to capitalize on it rather than supports (using the Red sweeper and the Scrying bloom for vision control in the early game). Once again, what I dislike the most is the "Major" status of this Rune as I fear players may not pick it because doing so would prevent them from accessing more powerful alternatives.
OVERCHARGER: Nothing wrong with this one, 10% CDR is quite powerful but the rune has a scaling component that accounts for that. I also like the bonus quality of life buff that allows people to overcap CDR without suffering negative consequences. Most champions would make good use of it, which makes it a healthy alternative ultimately picked according to playing style and personal preferences rather than whether a champion can make good use of it or not. Fully stacked, this Rune has a gold value of only 247g (excluding the overcap bonus) but the fact CDR is too hard to access for some champions and too easy to access for others kinda makes up for it.
ESSENCE THIEF: The concept is really cool but the rune needs absolutely a Max HP cap. Farm oriented champions like to spend a lot of time either laning or pushing side lanes, meaning they will easily be able to stack up to 300 HP by the 30 minute mark. Given Strength of the Ages was removed for its sheer power as it forced people to pick it simply to make up for the fact the enemy jungler was picking it first, I would suggest adding a Max HP cap set at something like 200 HP to prevent people from growing too strong in the long run and make other players feel a bit better upon opting for something else. Either that or upgrade the Rune to Major to allow access only to those willing to make a serious investment in sturdiness. This Rune has a gold value of 267g for each 100 HP stacked, with virtually no limit to it.
DON'T PANIC: Not much to say about this one, in general it's just a slightly weaker version of an already tested Keystone Mastery (Windspeaker's blessing). The power reduction accounts for the minor status compared to the Keystone status of windspeaker, meaning the rune should be pretty balanced. I like the fact it allows players to invest in expressing a specific aspect of their gameplay pattern (in this case healing allies), I don't like the fact only enchanters/healers would consider picking this Rune. But then again, not everyone needs to like every rune as long as each individual champion finds enticing a significant amount of them (ensuring they always have a wide spectrum of choices to customize their playing style).
PANIC: In theory the Rune could have some very interesting uses on champions such as Tahm Kench but as long as you're forced to choose between Essence Thief or this one I don't feel this one is ever gonna see much use. Nothing wrong with the concept though, it provides benefits that are difficult to obtain with other means and that really shine in some very particular situations, effectively rewarding a very specific gameplay choice.
BLOODLUST: I don't feel very excited about this Rune because the moments its effects become tangible are very limited. Even right now whenever I find myself picking the Dangerous Game mastery I get the clear feeling I'm investing in a mediocre tool that will repay itself only at limited times whereas something like Don't Panic/Windspeaker allows for a more broadly and consistently impactful expression of my gameplan. Then again, I never played any of the reset oriented champions that would benefit the most from this rune (such as Katarina or Akali) so my judgement is probably biased. I feel few champions would really feel significantly happy picking this mastery but since it's a minor one I can close an eye on that. Some tanks would possibly feel good about it too (thinking again about Vlad and Mundo).
RUINED KING'S TRIBUTE: Aside from the scaling component added to the healing this is pretty much exactly like the Grasp of the undying Keystone. Balance wise this is obviously ok when we consider the single Rune itself because the Keystone already exists and doesn't create problems in its current state. Speaking more generally though, if the idea is to keep the Keystones' power level around the one they currently have, then there are definitely some anomalies to look at (i.e. Berserk being too strong, Stormlord Mandate possibly too weak).
PERFECTIONIST: I don't like this Rune at all because I feel it conceptually contradicts itself. It provides a boost in early game firepower that rewards the most those who want to trade actively and bully their opponent, however a heavy trading pattern implies more often than not trading some of your own HP and dropping below the 80% threshold as a result. Once again I feel only champions that rely heavily on self-sustain could make good use of this Rune, not to mention that while the rune itself has a gold value of 420-490, AP and AD are generally stats that are relatively easy to access even on first back, effectively making this Rune not enticing given how the new system will allow players to have only six Runes in total. At the very least I think the threshold should be lowered to 50% to allow the lane bullies who may want to pick this Rune the room for more risky plays.
(Part 1 of 3, continues...)