I think we need Arena caps put into place.
Basically as players start to smurf their way down to lower arenas it ruins the game for new players who are legitimately in those arenas.
So make a cap. Basically if you play in Arena 1 no matter what level your dinos are they do not fight in the arena at higher than level 4. Arena 2 maxes at dino level 8, etc etc.
Sure you can use your all legendary 20 dinos in arena 3 but they are going to be level 12 in that arena so that other players have a chance to actually win. That way you can smurf along at any level getting whatever DNA you want without ruining the play of other players.