I'm using Railclone to make things like armco, fences etc, with separate posts, front and rear polys etc. As such the vertex weld is required to smooth the lighting out - however the option at present is a bit simplistic. It'd be nice to have an option to make the weld respect smoothing groups. So it welds verts with smoothing group one together, and all those with two etc. That way I can setup the smoothing groups on the segments, and all the fence polys weld together automatically, but leave the poles alone etc. But also it'd respect any smoothing already in place too.
Not sure how feasible this is as a dev, but it'd certainly make things better from my practical usage, and reduce the amount of post Railclone generation steps.