Hmm well it makes me curious...
Optimum paladin nova, say at level 12:
- Suppose 4 attacks (2 base, one bonus action from something, one extra from haste)
- Suppose 75% hit rate, with GWF active.
- Burn three level-3 slots for divine smite
- Total damage per hit: 7 (base greatsword) + 10 (GWF) + 5 (Str) + 22.5 (5d8 smite) = 44.5
- Three hits total for 133.5
Optimum fighter nova, same level:
- 8 attacks total (3 base, one bonus, one haste, 3 action surge)
- Same hit rate and GWF
- Suppose a battle master, with five d10 superiority dice
- Six hits total, five with superiority dice added (via trip attack, say)
- Total damage = 5*(7+10+5+5.5) + 1*(7+10+5) = 159.5
That leaves some things out (crits, fighting styles, magic weapons), but is it missing anything significant? Otherwise it does seem like the paladin's 1/day nova is simply worse than the fighter's 1/short rest nova.
Doesn't mean you have to like novas, but it suggests that if you don't you should worry first about the fighter?