Uppercut and its morphs needs little tweaking before going live. I understand the logic behind the change, problem is it isn't really working that way. Noone is using it in pve, where this change would make sence(probably), but in pvp there is not such a thing like "using several uppercuts in quick succession". It might be the case with snipe and dark flare, because they both are ranged abilities and there is a possibility to cast them in quick succession, but this does not apply to uppercut.
Uppercut is a melee casted ability, very risky to use, and its all about that one big hit creating an opportunity to kill your target. As it is now on live, its more about waiting to your opponent to make a mistake a get himself hit by it, and punish that mistake. Its very easy to avoid, and you probably miss a lot of uppercut before you land the one hit that makes difference. You could say its high risk, high reward ability (although with current pvp lag is more high risk, average reward ability), and change you are planning to do makes it high risk, low reward ability and effectively kills uppercut playstyle. I know its dying playstyle anyway and less and less people are using it, and that is one more reason to rather examine and rework that skill, not nerfing it.
Even now uppercut and it morphs are widely considered bad, weak skills, and reducing its damage while gaining virtualy nothing in exchange does not make it better. If you really want to reduce the damage of uppercut, I believe reducing cast time as well is the right way to go. It does make uppercut easier to land while not hitting as hard. You already buffing flurry damage to be on pair with other "melee spammables", why not reduce uppercut cast time to 0,6 sec and reduce damage accordingly to make this skill somewhat useful? Because if the proposed change goes live, people just take Masters 2H and use cleave instead, with no cast time, AoE cone and same damage with bleed/shield instead of stun.