You have a very good point about the definition of "construct," I think it could be very annoying down the line if they implement the item and have a bunch of weird edge cases. That being said I feel like this idea is still worth it, especially for characters like the upcoming Graves.
I think...
Addendum: I'm not married to the idea of the item being Tier 4, so maybe having the dagger be tier 3 and having a tier 4 upgrade would be better. The tier 4 could either remove buffs when it hits a player just like old Capacitor, or the much more funny option would be to have the dagger work on...
I had this idea for an item that specifically counters stuff like Doorman door, Kelvin Icedome, McGinnis' everything, etc. It's a tier 4 active that you throw at the target construct to dispel it. This would partially refund cooldown to the person who placed the construct and would place the...