Many engineers are not using RSA because of its' old and weird interface. Although RSA is very capable and full of very advanced features, people won't use it because the interface is a hassle. Advanced features require opening cascading windows, the closing them up. I mean, it's worse than V/G in Revit.
It is a no brainer to have a common interface. It would save a lot of time for both engineers and software maintainers. I prefer a big window with many tabs (like V/G) instead of many small cascading windows. Everybody would be using a large screen these days, we ain't working in Windows XP anymore.