While the Samus miniboss is essentially a runner with better health and an actually deadly weapon, I feel the GentleSpy miniboss is the less useful/more stally of the two.
The gentle has the cloak and the quick movement speed letting it escape certain death provided it didn't cloak. Long story short, glorified infiltrator with a irritating cloak, probably don't need it.
I get that Samus can double jump and run around the map as a runner could and would do and while I don't think I have ever really seen someone stall the game with it, I can understand it.
Just my 2 cents.