Balance/Overloaded skillsets
League really should have more skills with counter-play mechanics like Blitzcranks W overdrive (ACTIVE: Blitzcrank puts himself into overdrive, gaining bonus attack speed for 5 seconds and bonus movement speed that decays to 10% over the duration/When Overdrive ends, Blitzcrank is slowed by 30% for 1.5 seconds.) Really help ease balance issues with certain champions skills and kits. Plus with the endless re-works, new champions, kits seem to become more complex and fancy with seemingly no drawbacks leaving older characters in the dust. A champs stats and ratios don't always need to be tweaked. Problems arise from the utility their kits can provide, these issues can be addressed by adding more mechanics like overdrive to other moves.