you can simply zoom in with the camera. it shouldn't be a big problem to find the vertices you want then.
Suppose you want to select a group of vertices to form a specific pattern with a reasonable accuracy
For example a "beating heart" same as you can see in some cartoons
You would agree that it is not that easy to do it zooming in / out a 10000 vertices model
if the indices stay the same depends on your modeler and pipeline. i guess with some it works, with some not.
This is exactly my concern
I am more confident in built in tools rather than relying on universal converter
Maybe in this case there is no any problem
However ask the Cinema 4 users how happy they are of the FBX exporter od the new R12 release
by the way, i think most mentioned examples better get done with bones and not by manipulating vertices.
Generally speaking , I agree
But with some organic deformation ex the beating heart I dont think that bones are the best solution
uUnity does not suppot vertex animation ( Unless I am still wrong
)
In some situation vertices animation it is still the way to go
Last just to avoid nervous reactions
We are talking about minor issues
In general I am convinced that Unity is as flexible as 3dgs