MYMU AP Items Update Buffs Mage Mana and Combat MP5
Yes, I am serious about that. When the info about the items first came out, I - like most people - was a little concerned about mana and mana regen for mages - specifically mages who like to spam their abilities for poke and waveclear. However, trying to think of a solution for it, I did a little math and found out that... it really doesn't need any solution. Why? Because of this guy: 
. Specifically the:
> * Additional Passive - Awe: Refunds 25% of Mana spent
This might get pretty long, and there are some maths involved, so here's the TL;DR version first:
- Tear of the Goddess will give significantly BETTER mana regen than current mana regen items for champions with high cost and/or low cooldown abilities (with the exception of the Mana Font passive on Chalice and Grail at very low mana). The "Awe" passive gives an injection of mana that actually ends up giving you more mana than you would have gotten with increased mana regen (maths below) while you are frequently using abilities.
- Mana added to items (Morellonomicon, Hextech Frost Cannon, and future Lost Chapter builds) increases mages' mana pool, allowing more spells to be cast before going OOM. Especially in conjunction with Tear and Archangel's Staff.
- Yes, you will still go OOM eventually, and you won't have Athene's Grail to bring you back up super quick. But the first two points will keep you from getting OOM for a VERY long time compared to now. Basically, you can fight for longer, but when you're done, you're done.
So anyways, on to the meat (and the math).
Tear of the Goddess, and Why It's Better Than MP5:
With the new passive, Tear will easily outperform any current individual item with MP5 (again, excluding Mana Font when you are at very low mana). Throughout the rest of this post, I will be using Ziggs as an example since he is one of the "Long-Range/Artillery" mages everyone seems to be worried about.
I'll be using Ziggs' stats at levels 6 and 18 for comparison between the current regen system and regen with the updated items. At level 6, Ziggs has 619 base mana and 10 MP5 (2 mana per second). At level 18, he has 1183 mana and 19.6 MP5 (3.92 mana per second). All numbers and calculations used are assuming no runes or masteries influence mana or MP5. I will also not be including the "Mana Font" passive from Athene's Grail, since that would be fairly difficult to calculate in, and just looking at generic numbers, I know that it would be more powerful than the new Tear passive as you lose more and more mana.
At level 6, we will assume that Ziggs has 3 levels into Bouncing Bomb, giving it a 5 second cooldown and a cost of 60 mana. At level 18, we will assume he has maxed Bouncing Bomb, giving it a 4 second cooldown and a cost of 70 mana. Here, we will compare Ziggs with two different possible builds - a "normal" build with current items, and a theoretical build using the updated items. For each build, we will assume that Ziggs uses Bouncing Bomb whenever it is off base cooldown (not accounting for cooldown reduction) for a 60 second period, then compare. I will refer to the two different Ziggs as 
Ziggs and Ziggs.
Ziggs:
Lvl 6 Mana: 619 MP5: 10 base --> 20 w/item
Morello Ziggs has an additional 100% base mana regen from the item, which gives him a total of 20 MP5, or 4 mana per second. For each 5 second period between spellcasts, he will regen 20 mana. There are 12 spellcasts in total, resulting in a total of 720 mana used, and 240 mana recovered from his base regen, leaving Morello Ziggs with 139 remaining mana.
Ziggs:
Lvl 6 Mana: 619 base --> 869 w/item (no stacks) MP5: 10
Tear Ziggs has just his base mana regen of 10 mana/5 seconds - or 2 mana per second. So, for each 5 second period between spellcasts, he will regen 10 mana. However, he is also refunded 15 mana each time he uses Bouncing Bomb due to Tear's "Awe" passive - 25% of the 60 mana cost. Add this in, and Ziggs will regain a total of 25 mana during each 5 second period. Over the 12 spellcasts, he will again use 720 mana but will recover 300 mana. This leaves Tear Ziggs with 449 remaining mana - more than three times Morello Ziggs!
What does this mean? Well, once you have Tear (and you can pick it up before level 6), you can SPAM your Bouncing Bomb nonstop for more than 2 TIMES as long as you could with an additional 100% Base MP5. Beat down your lane opponent with nonstop harass, clear all the minions and push your lane, force your opponent out of lane - then back while it's safe to replenish mana and buy some goodies!
Also note: Tear of the Goddess only costs 750 gold, while Morellonomicon costs 2400. Meaning you get more mana and better mana regen and you still have almost 1700 gold to spend on other items (Needlessly Large Rod, Fiendish Codex, etc). And you can get the better regen item earlier than you could Morellonomicon (or Grail)!
Still not convinced? Here's the level 18 test (again, only using the two test items):
(Assuming Bouncing Bomb is maxed out - 4 second cooldown, 70 mana cost)
Ziggs:
Lvl 18 Mana: 1183 MP5: 19.6 base --> 39.2 w/item
At level 18, Morello Ziggs has a total mana regen of 7.84 mana per second. Each 4 second period between spellcasts, he regens 31.36 mana. With 15 spellcasts, he uses a total of 1050 mana and regens 470.4 - leaving Morello Ziggs with 603.4 mana.
Ziggs:
Lvl 18 Mana: 1183 base --> 2183 w/item (assuming item is maxed by this point) MP5: 19.6
At level 18, Tear Ziggs recovers 3.92 mana per second. Each 4 second period, he recovers 15.68 mana, and is refunded 17.5 mana - a total of 33.18 mana each period. Over the 60 seconds, he uses 1050 total mana and regens 497.7. This leaves Tear Ziggs with 1630.7 remaining mana!
Using these numbers, Tear Ziggs can go for nearly 4 minutes constantly spamming Bouncing Bomb before he runs out of mana, with no items, runes, or masteries other than Tear of the Goddess. By comparison, Morello Ziggs can only spam Bouncing Bomb for just under 2 minutes before going OOM (less time, if you factor in the CDR from Morellonomicon).
Here are the numbers at a glance:
Total mana regenerated -
- Lvl 6: 240 / 300
- Lvl 18: 470.4 / 497.7
Total mana remaining -
- Lvl 6: 139 / 449
- Lvl 18: 603.4 / 1630.7
SO, especially at early levels, Tear of the Goddess is more effective for in-combat mana regen than an item providing +100% Base MP5. And, the higher the mana cost and lower the cooldown of an ability (especially mana-per-second toggle abilities - 
and 
), the more effective it is.
Add to that the additonal mana on some AP items and the possibility of new AP items with mana in the future (Lost Chapter upgrades), and mages will now have HUGE mana pools that take a long time to run out. But, yes, once the pool is empty, it will be empty for a long time - which is really one of the intended weaknesses of mana users. You have lots of your resource, so you can go for a long time without refueling, but once you run out it's probably best if you recall.
Currently, a good Ziggs build might look like this: 
. This gives 621 total AP, 40% CDR, 200% MP5 + Mana Font (Combined, are definitely better than Tear on it's own), and a few other stats.
A good build after the item updates might look like this: 
and maybe 
(not 100% sure whether any of the new Hextech items would work better for him - I'm clearly not a Ziggs player). This build gives 769 total AP (at full stacks for and ), 1800 additional mana, 20% CDR, and the "Awe" Passive - again, with a few other bits and bobs.
Not only do you have more mana and significantly better mana regen early, you also have over 150 more AP. CDR has also been added to other potential items like Zhonya's and Abyssal Scepter, which would still be useful choices if you HAD to have more CDR - at the expense of some AP and possibly mana.
As I have stressed several times in this post, YES - you will eventually go OOM. But it will take a LONG time. And, honestly, I like that. It differentiates mana users from energy users and resourceless champions. Energy users are extremely limited by their small resource pool - they can pull off their combo, but not much after that - but their energy replenishes quickly, so they can hang out for a minute or two and be good to go again. Resourceless champions have long cooldowns that restrict them, but they never have to worry about running out of fuel. And mana users have huge resource pools that allow them to continually apply pressure to their enemies for long periods of time - but once they run dry, they stay dry for a while.
For waveclear, harrass, and champions that just like to use their abilities all the time - these changes are a HUGE BUFF! You will have a lot longer to use your abilities before you REALLY need to ration your mana, and you have more options to add powerful items to your build, rather than being stuck with a kind-of crappy item that you only want for the mana regen and CDR.