It is because they tried that before. People specifically needed isida and freeze banned. Even in the most recent daily cup, there was a team with 2 freeze mammoths and a viking isida and 3 attackers, and the 2 mammoths just sat on the flag with the isida healing them. They received no flags.
It does make me sad though that there are people who do this, they should allow twins and firebird, those are both dynamic. Vulcan also would be good for star series and is the "Moon Series" I play with my friends. It is still pretty fun to watch.
Customer support service by UserEcho