Why some Virtua Fighter 5 stages were changed (VF5, VF5R, VF5FS, VF5US/VF5REVO)

I want to ask you guys about stage changes/replacements, for example, Deep Mountain in OG VF5 was a daytime "mountainside" rooftop-like temple, with fences (not open), where the ring out is you fall off of the "deep mountain" to a "long way down" (size is low fence 12x12), but it was changed in VF5R onwards to a "river-like" stage where ring out is water, has left and right fences that tall and open (no fence) areas to water (size changed and shrunk to rectangle 6x16) and from VF5FS onwards it was changed to night with some lanterns, and Sanctuary was replaced by Genesis in VF5US/VF5REVO. Why's that, or why was that?