I have to say, I like Pentagon I.  It is pretty impressive considering when it came out.
 
However, there are a few things they could update:
 
1. A new preset management system.  Trying to find something in the current bank system is a bit awkward.  If they made one change, this would be the one I want most.
2. Allow import of standard single cycle waves, as Z3ta+ does.
3. Separate the effects out into another page. 

I highly doubt Cake is going back to pentagon to referb it.  It is 5-6 years old and superseded by Z3TA, Dimpro and Rapture.  I doubt if the programmers are still around, since they brought in René right after it came out.
 
A newer analog virtual would be nice, even basing it on Pentagon.  Maybe hexagon?  You might try a feature request, tho. 

I've actually submitted most of these as feature requests.

I agree with AT. Very doubtful since ,interface aside, other Rene synths cover much of the same ground. The fact that Pentagon has had the valley simulator issue for years that causes potentially equipment damaging levels and did not think Pentagon important enough to have one employee spend the dayb fixing it speaks volumes. I think any new cake synths are going to either be to fill void of something not available in Sonar or something atttactive to and marketable to non-Sonar users. A solid but simple subtractive synth may not fit the bill. Z3ta had enough non-sonar users to justify update. Rapture may have enough potential due its raw power that I would not be shocked by a Rapture 2. I love Pentago but I just don't see it happening. Keep putting . In the suggestions though because you never know.

I like Pentagon a lot, too.