I think removing buffs is a ridiculously strong effect and should only be on T4 items. I agree that curse is too strong, but a large chunk of T4 items are powerful buffs, having a T3 item that counters diviner's kevlar, infuser, colossus, all bridge buffs, etc. while also shutting down characters who rely on their buffs to function (Billy Blasted, Abrams Siphon Life, Seven Power Surge, Viscous Cube, etc.).
I think the reduced healing and barrier are fine though! The debuff duration is short enough that for most people, if they just wait it out and apply the barrier after, they'd be fine, but one misuse of the barrier and it's basically wasted. The healing debuff is a good counter to mcginnis healing aura or dynamo healing if you've got someone in mind to cancel out.
If you want to keep removing buffs, I think this ability needs a much higher cd, so it can't be easily cycled on most T4 buff items in the game. Otherwise, I think instead it could just remove the target's shield specifically. (Though this would still counter Diviner's Kevlar a bit too much)