Polymorph is resources spent.Please a caster spending resources to cast a AOE spell for situational aoe damage, a fireball deals 28 damage...
T-rex doesn't do single target damage. 2 target damage on fireball is 28*2 = 56, save for half on each. The TRex cannot attack the same target with both attacks, and they do 33 and 20 on average each.
A level 8 rogue with booming blade non magical rapier and a reliable reaction attack deals 2d8+4d6+4 27 damage per attack, twice per round. Often on one target.
A PAM GWM fighter with a flaming glaive does 2d10+1d4+6d6+42 = 71 damage. They do have to burn superiority dice on precision attack to make their accuracy decent; only 41 without using GWM.
A sharpshooter with +1 bolts and a +2 hand crossbow does 3d6+51 (61.5) at +8 to hit.
Yes, polymorph is strong. No, polymorph is not usually huge damage increase. I mean, it is great on unoptimized characters.
But I find mainly its offensive boost is a horizontal thing, and a bucket of HP to keep someone in the fight. Those HP aren't as good as real HP, because they are backed up by poor AC, but they do soak damage.
Polymorph also peaks at level 7/8.
Although, one of these days I want to see what a hasted, tenser's transformation'd great ape fights like.
