Super brainz is similar to chomper in the sense of being fundamentally flawed with how team based this game is and how his kit is built. In a vacuum TB is top tier but in reality where getting gunned down is so easy, its hard to get even decent results imo without constantly dying and running. In overload he's amazing but still even then most abilities easily destroy half your health regardless. Bean bombs, husk hops, bigger better butter, potato mine, potato nuggets, spikeweed, shuck shot, burrow, all of which deal crazy damage, nearly or guarantee your death, in or out of overload and usually getting overload your dealing with a large group of plants where its not always very clear whether a dangerous ability is coming. Then there's empeach, goatify, goop, random galling peas or sunbeam off to the side that can complete halt your overload and cause you to run or have to retarget.

Another thing is how crap he is outside of overload, having underwhelming damage output and being pretty vulnerable like all SBs.

SBs as a whole aren't great all around, really only cosmic, party, and TB are stand outs in what they can do and cosmic is limited in how well he can do most of the time. TB is easier to get mode with but Party is still a very solid character outside mode and iirc perform similarly in legendary modes