Been playing for a while. For some reason after so long playing, I've only just started to think about heavy attacks and how they might be adjusted to feel... Better.
Off the bat, bow and staves are fine; projectiles only really have two options for aesthetics. Big hit or channel. But two-handed, dual-wield, and sword-n-board could use some love.
Let's start with two-handed. Anyone that knows a little bit about self defense, or even fight choreography knows that telegraphing a hit is usually a bad idea. And two-handed heavy attacks are (cosmetically) two-second windows that leave your head, core, and limbs entirely exposed. I say instead of a huge wind up, you enter a guard position (weapon point out, raised high, parallel to the ground) and then spin in a horizontal slash as the attack completes charging. Make the hit feel abrupt, fast, and powerful. Not entirely dissimilar to the execute ability, but without the jump, and horizontal instead of diagonal. The timing and numbers of this heavy attack are otherwise identical.
For sword-n-board, I think we can take inspiration from a certain green-clad adventurer that players often cosplay with their outfits. Present shield, hold out sword behind and straight, and then spin, bringing the sword under and up for a big hit. If we were talking mechanics it could even be the only AOE heavy attack (besides the storm calling ult), but just the aesthetic adjustment would make a huge difference in characterization.
Dual wield has the same issue two-handed does. Let's make it a channel. As the player holds down the attack button, rapid, successive light attack animations play. The last hit in the channel could be the current heavy attack animation, but I wouldn't be opposed to reworking it to be a more meaty follow-through, either an over-handed slash, or an under-handed swipe. As long as the last hit conveys a heavy final cap to a combo, it'll feel satisfying. On top of resolving the telegraph issue, this would also bring back a lot of the ferocity we lost when the flurry animation got re-worked. This animation would be equal but opposite to flurry-- instead of a measured technique, it would be an elemental succession of blows, each of which needs to be felt with solid, distinct audio.
All timing and values would remain the same, unless we consider the AOE sword-n-board adjustment. I'm more interested in the aesthetic of heavy attacks as far as this thread goes, and since changes like this are on the table according to the director's letter, I thought I'd share what I feel would really enhance my experience.
Thank you for coming to my T E D talk