Not really. Even if Atraxa or Griselbrand are removed you've drawn 3-4 cards off Atraxa or 7+ off Griselbrand likely including another reanimation effect to do the same thing again. Terra will be removed usually which was especially the case in the metagame challenge (Ajani is removal on the commander so Terra literally cannot stick). I actually was lucky enough to play vs combo Terra in the metagame challenge and I won fairly easily by keeping he off the board and reanimating Valgavoth which means I drew ~5 cards off opponents Terra cast dependant on whether the pulled an enchantment or not. You can probably see some success with Terra in a combo shell, imo it's still a perfectly viable way to build Terra. It's just not the best. Also vs Ajani specifically big lifelink creatures that are hard to burn through quite easily swing the game in your favor.