Good idea. Critical hit/finishing hit animations/audio, would bring more variety to combat.
Other animations I would like to see worked on once more "important" stuff like making believable ladder-climbing giant bulls is done
1. Dodge & block animations. Having dodge/block animation play when dexterity/shield is enough to make the difference between a hit and a miss. Would bring much needed variety - as well as somewhat placate the vocal critics of the RNG-nature of D&D, many who see outright miss as a personal defeat they are unable to change. This issue is partly why Larian is over-incentivizing tactical positioning like height and flanking.
2. Responsiveness to flanking. Flanking is a cheesy mechanic currently. Advantage is guaranteed and the way the AI are unresponsive to flanking reveals turn-based combat as an entirely unrealistic approximation of real combat. Having everyone automatically turn towards a *single* opponent threatening them would counteract this issue and bring some balance and immersion to melee combat. In effect, two people would be needed for flanking (one to grab the attention, the other to flank) unless the enemy is surprised.
3. One-handed spear animations. In D&D spears are versatile weapons that can be used one-handed with a shield or in both hands. Bring this back.