Need more META diversity
Not going to suggest that other MOBAs are better... but League has had too stagnant of a meta for too long. Most dota2 characters have been around for years before LoL was conceptualized... and are still essentially unchanged... because instead of constant rebalances and reworks to keep people in line, they have a variety of champions which excel differently. Same with HOTS... apart from some of it's down-sides, my favorite aspect is the specialists. An entire class of champion is there to "do stuff differently" and be particularly good at a certain strategy.
LoL has been stagnant for years. We get new champions who does the same thing we've always done, but slightly different, perhaps with slightly different recommended items. We need -different- mechanics. I'd really like to see champions which allow for different strategies. Not just buy wards and stall until ADC fed.