Roots has more defensive cards (Yookie, Jeena, Arno, Flora) and more attack manipulation (Rico, Gertian, Jeto, Miken Moose) than GHEIST, so if they have Lou in Elo, encounter them will be like you play against Junkz, GHEIST and Pussy Cat at the same time.
But now using Roots become more and more difficult, UR give Yookie back, but take both Jeena and Gertian from us. So Roots now is not as heavily defensive as it used to.
Try not to look at bans as only a testament to the strength of a certain card. There are absolute crap cards that are banned for the sole purpose of weakening the clan as a whole, and not because the card is particularly overpowered.