
With RTC, IBM are only trying to get back in line with the rest of the modern ALM products. Like it or not, the notion today with most software products is to sacrifice flexibility in favor of usability.
I guess that, for most development efforts, all you need is the ability to quickly setup a project and apply one of the cookie-cutter methodologies.
UCM was a wrong step in that direction, something IBM fixed with RTC.
ClearCase Base was designed to be extremely flexible and configurable, and my guess is that anyone who is using it right now, will continue using it for a long time. Anyone else has already moved, or considering a move, to a more modern tool.
ClearQuest is a different story. Considering the amazing selection of useful, feature-rich, and cheap issue-tracking tools out there, I'd say its days are numbered.