It's necessary though. ADCs building the same cookie cutter stat sticks every game was boring and not good for the game, not to mention that the previous itemisation changes to mages, juggernaut reworks and items and even last season's jungle changes had ADCs fall by the wayside. Their "weak early, strong late" power fantasy fell by the wayside and every other lane had far more impact on the game.
Yes these changes could be too much one way or the other, BUT the changes are needed to make the class much more diverse and to help those champions better fulfil their fantasy and their role's fantasy.
Obviously I'm not a designer so this is just my personal opinion as a player, but I feel this will only make the game better.
I would say teleport helped tops have more impact early-mid game.
Mages are...mages. Being in mid allows them to flow between top and bot.
ADCs have always been....ADCs. After a while, left unchecked they become monsters whether or not their early game was bad or good.
Even now in pro games, the focus of having a strong ADC is incredibly important. That's just how the game feels. Between the ADC reworks and the new items they're getting, to me it seems like it pigeon-holes the idea that ADCs are what a match should revolve around.
Like, the change with grievous wounds...it only affects self healing....the only reason you would nerf grievous wounds like that is to buff bottom lane. Very rarely do you have a top or mid lane that can give an incredible heal to an ally. That's usually relegated to just support who fill in the healer role.
It's a huge buff to characters like Soraka or Sona, and an indirect buff to ADCs early games because of that fact. Suddenly Ignite isn't all that great at bottom lane, and kill lanes are phased out just like that because of ignites weakness in bot lane. So it's going to create this cycle, if grievous wounds aren't reverted to what it was, of nerfing the healers yet again.
also, mages have been the dominant mid lane class through the entire season and had big buffs in the itemisation changes.
Even if these changes end up being a net slight nerf to them, I'm ok with that. Other things need their time to shine and I'm sick of playing against Ahri, Lux, LeBlanc, Orianna, Viktor etc. etc.
hate to break it to you, but those mages are still going to be played. They weren't played because of the items, I can tell you that much up front. If you don't understand why they were played, then well..
