previous title: Should uppercut have it's cast time reduced to 0.6 seconds?

The reason is, against any good animation canceler or macro user, instant cast abilities reign supreme. Here's what I mean:

Edit: so apparently uppercut can't be interrupted. which is strange, as it is a cast time ability.

You can anim cancel a light attack into an instant cast ability. you can also anim cancel an instant cast ability by blocking, and you'll still do damage. Since shield bash isn't constrained by the GCD of abilities or light attacks you can also LA+InstantAbility+shieldbash . If you're good enough at animation cancelling you can perform all of this in under a second, repeatedly. Since Uppercut has a cast time that can be interrupted (and stuns the user if interrupted while not under CC immunity), and it deals damage after one second, that means a good player using LA+Insta+Bash can deal more damage to a player using Uppercut in less time than it takes for Uppercut to cast, as well as procing three different damage instances (or more depending on the insta used, enchantments, procs) and stunning the player who is using uppercut. They can do this repeatedly, and fast enough to never let the player using uppercut to get a hit in. And even if the player using uppercut does get a hit in, since the only time the LA+Insta+Bash player doesn't have their shield down (damage and negative status effect mitigation) is when they use the LA+insta which can be done in less time than the GCD and the Uppercut cast time, they are also greatly protected while doing so.

In Summary, the current risk/reward for the 1.0 cast time of Uppercut carries too great a risk for a reward that is highly likely to be mitigated.