"Immortal" teams are a legit team strategy. How about we remove "Blitz" because it is the easiest to play and most rewarding? No. Water main and Earth main (The two top contenders for Immortal teams) do not excel at damage in any way - they are forced to heavily rely on their team to either:
1. Do enough damage, or
2. Live long enough and win to round limit (Immortal)

Just because you dislike fighting a team setup, doesn't mean it needs to be removed because you can't win.
Every team setup has some form of weakness, you just have to find it.