now i dont use the skill but i dont think any skill that has a very limited range should be inturuptable and if you really have problems with the people spamming it all you have to do is walk through them or stand inside them i know its not easy but it works wonders bcuz most these people using that abil only seem to have that one abil as damage and therefore can do nothing maybe try it out? hope i helped in some way shape or form

I am on the fence about whether it should be interruptible again or not. It is spammed to oblivion, and buffs itself. In 1.5, the damage buff did not apply to Wrecking Blow, punishing the spam. However, being interruptible makes Uppercut nigh useless against players familiar with the mechanic. (Once a player knows the tell, they can reliably interrupt Uppercut - from personal experience.)

But to help people out in the meantime, Uppercut is strong but has a one second cast time. That is one second where the user cannot perform any other action besides basic movement and block-cancelling. That is one second where the user is perfectly exposed to any instant-CC abilities.
To name a few non-class specific instant-CC abilities off the top of my head:
Power Bash (One Hand and Shield)
Shield Charge (One Hand and Shield)
Scatter Shot (Bow)
Destructive Touch (Destruction Staff)
Silver Bolts (Fighters Guild - assuming opponent is vampire)

These skills are available to everyone (with the skill points and prerequisites). There are also class specific instant-CC abilities, such as Piercing Javelin, Stonefist, Bolt Escape, and Aspect of Terror.