[New Mode] Skill-Up
In Skill-Up, players have to make strategic choices about leveling up their skills. They can only put one point into each skill, but that point gains effectiveness based upon Patience Points that players earn as they level. So, for example:
Player A chooses to use Garen. When the game starts, that player gets the usual skill point available. They decide to put that point into W, since it will give them a steady boost to their resistances throughout the game. However, that skill will forever be at level 1. When they hit level 2, they get another skill point, but they decide not to spend it. They hit level 3, and this time instead of a skill point, they get a patience point since a skill point is already available. Now, if they use their skill point, they will get 2 levels in that skill for the rest of the game. If a player were truly patient, they could wait until level 5 to level their first skill. They would then, as a reward, have access to a rank 5 talent at only level 5, but at the cost of 4 very difficult levels and the added utility of multiple skills.
Upon reaching level 6, players get the ability to level their ultimate using their available skill point. Ultimates use ultimate patience points, though, instead of standard patience points. These are gained at levels 11 and 16. So if a character takes their ult early, they have access to the early utility, but the ultimate will never reach its full potential.
The "zerg rush" build would be level 1,2,3,6 for all 4 skills to be rank 1 The most powerful late game build would of course be levels 5,10,15,16 to level all 4 skills to be max rank.
I believe this mode would lead to some interesting strategic choices. It could be pretty fun.