I am trying to develop a fighting game, and because of the way such games are structured, it is much, much easier to work with the mechanics when I know everything functions at the same speed, and the smallest unit of time is uniform. Moves can be balanced easier and hitboxes more carefully designed, and such.
The problem is that there really is no easy way to initialize timers, animation players, etc. with the unit of time being, for example, 60 frames, instead of one second. This makes it very hard to work in an environment centered around a different metric, made with different assumptions. I'll agree that an unlocked framerate is ideal for 99% of cases, but this is a niche that I am worried is not being addressed by the Godot developers.
Otherwise I am extremely impressed with this engine and I have no plans to use anything else at this point. This is just one of the very few frustrations I am having with it.