Putting a fresh face on the Sonitus suite might seem like a trivial undertaking, but AFAIK there is only one coder working on Cakewalk today, and his priority is making the transition happen smoothly. Next on the priorities list will be pending bug fixes and enhancements to the core program. Much further down the list will be updating bundled freebies, and even then the emphasis will be on stability and features rather than cosmetics.
Looking at the Sonitus plugins, I'm not seeing a lot of justification for the "long in the tooth" accusation (one that I've made myself, btw). They still sport some of the cleanest, easiest-to-use UIs around. The compressor is still a favorite for sidechaining, and the multi-band compressor is one of the clearest, most straightforward implementations I've seen. I have to admit, though, that I've become spoiled for resizable GUIs.