The game needs an overhaul with champion roles better defined. Damage cannot be so dominant. Teamfights are a stupid mess with assassins melting tanks, adc's assassinating mages, skirmishers out-tanking tanks, etc.
In my opinion, many health problems with the game could be fixed by increasing tank survivabilitity -- especially versus assassins. Many other problems could be solved by making resources -- energy, mana, and cdr -- more scarce and more valuable. Rarely outside of laning phase do I think "we can win this fight if we can outsustain their mana".
Increase resistances but reduce health of tank items. Give tanks active items that use mana to create shields that strongly scale off of resistances (so a tank with lots of resistances can get maybe 3k hp in shield while mana lasts). Now tanks are MUCH stronger against lethality/mpen building assassins. But their durability is gated by mana and a long fight favors the carries, who need to build lw to kill tanks. This restores the trinity of teamfights -- assassins want to kill marksmen, marksmen want to shred tanks, and tanks want to disrupt the enemy assassin or lock down the enemy carry. To further this goal, lethality items need more lethality but less ad. Armor should be able to go negative, like it did in previous seasons.
Other changes that are needed: assassins need more of their damage to come from missing health and less of their damage to come from other things. Assassins should not be killing full-health targets; rather, poke mages, skirmishers, tanks, and other classes should soften a target before the assassin goes in.
There are many other problems with the game. There need to both be more reasons to teamfight and more reasons to splitpush. Itemization does not make the strategic tradeoffs sufficiently stark. Riot really didn't like the old passive on aegis because it was invisible power. Fine. But there need to be other items in that niche that reward teams for sticking together. At the same time there need to be better reasons to leave the team to splitpush; e.g., something like the altars in Twisted treeline -- if you capture the enemy altar, your team does increased damage to shields.
No champion should be hard countered at the start of the game, but there need to be more builds that hard-counter one strategy but are hard-counted by another strategy. If you make a strong build for teamfights, you should lose if the enemy is able to out-maneuver you into a splitpush game.
