"Stability" means various things to different people. I think it means more than just not crashing. The program should function properly without hiccups or dropouts.
I had recorded eight complete projects in X1, all of which ran flawlessly and were ready to allow many more tracks to be recorded. I opened each one of those projects in X2 and X2a, and saw significant performance issues in X2a. No more tracks could be recorded in X2a--immediate dropouts. (This was not the case for X2, which was buggy in other ways, mostly dealing with take lanes.)
I do keep some unused tracks archived--just for kicks. I'd say I average about 20 tracks archived. My theory is that X2a cannot ignore archived tracks the way X1 (and X2a) could. Just a theory, but the fact is I can't use X2a to continue working on older projects. I'll see about new projects.