Been looking at something like the C1 Maniac which has a sliding hook.

Is boosting less effective or wobbly with a slider bar or rope?

In short...No.

It takes 1 - 2 sessions to get used to it then after that it becomes a great advantage.
Boosting is no different.
Just replace your dyneema 2-3 times a year so you know your safe.
Prevention is better than cure.

I swapped over to sliders a few years back and at that time I was still getting my boosting down pat. It helped me quite a lot. The extra freedom of movement made it easier to scoop and pop and I improved my boosting quite a bit.

I guess it comes down to a feel thing. None of the top twin tip guys use sliders but I guess they would all still want to unhook

Feels weird for a while. Then you get used to it.

Unhooked tricks require extra height
.