If it works as intended, yes, sort of.
My intended sequence would be:
- Make PSV parameters and start to generated a world.
- Interrupt world generation immediately after the generation of the geography (before caves are placed, to avoid moving those to stupid places such as the bottom of an ocean) to use the new functionality to touch up the world where DF "generated it incorrectly", such as e.g. placing lakes where they shouldn't be.
- In this phase, I'd also "correct" DF when it comes to assignment of evilness to regions. It should be possible to bypass the clunky assignment process to some extent, but it requires a fair bit of work as you have to deal with one tile at a time, so it's better used as a finishing touch thing than as a replacement for PSV planning.
- Some non DF supported things should also be possible: Regions of the same type beside each other with different evilness, for instance. I can e.g. think of using PSV to create a 3*3 region that's then converted into two regions where one is a single tile one in the center, so the outer region might be good while the center is neutral to allow for placement of a human civ there.
- Add/adjust flora/fauna for all the regions modified.
- When all the setup has been performed, resume world gen. If it works as it ought to, the changes should integrate seamlessly.
It should also be possible to use it to generate an embark region (or, for that matter, an embark plus 8 surrounding regions). Again, flora/fauna has to be added, but you should be able to tweak the embark to your biome liking that way, possibly skipping the PSV stage completely.