Imo the dificult increase in GW is so bad for the game, u need sometimes a hour or more to complete current crazy hard GW while a few monts ago u could complete it in 10-15 min using much worst teams than today... It doesnt matter how long u progress in the game or how much u improve ur squads, because those last nodes are almost imposible to beat (for an average player) whitout losing a couple of ur best toons, or without retreating a lot of times looking for good RNG...
It makes the game really time consuming and its really frustrating having it as a daily task... Because its so good to have hard challenges in the game SOMETIMES, but to have them EVERYDAY (3-4 hard nodes who need like 5-10 restarts each one) is really anoying :S