How to buff OTHER summs so that Flash is not mandatory?
Flash is here to stay. But if you want to have constructive discussion you should be thinking about how to buff the other summoner spells. Namely:
Ghost Heal Barrier Exhaust Teleport Cleanse Ignite
In addition to tuning CDs, here are some ideas for each summoner spell. Options are very limited though.
Ghost: slow resistance Heal: slow resistance, AoE Barrier: increase amount/duration Exhaust: increase amount, maybe some kind of anti-tenacity Teleport: nothing other than CD, but this is pretty busted in pro play as is Cleanse: nothing other than CD Ignite: probably fine the way it is
and
ults, and apply Grounding.