I am a mostly midi and soft synth person. I felt that Sonar's synth are getting old and needs to be updated.
PSYN II has been around and left untouched since the days of Project5?
Pentagen too can use a lot of improvements. It is still buggy. Some of it's patches are too loud. A better patch browser is needed too.
Dim Pro sure can use a lot of improvement too. I can use a slider or knob ADSR. Better build in effects? I am too lazy to write sfz file. I would love to have graphical way of inserting multisamples. And I felt that the dynamic range of the instrument can be better too.
Rapture too can use a better step modulator. It's timing subdivision is too limited.  Again I still prefer ADSR knob or fader.
 
 
 

Pentagon is no longer bundled with SONAR so updates are unlikely for it.

the too loud patches in pentagon are actually glitching because of the Valley Amp sims. when you see one of them, disable that and save it. that said, it's still dangerous to use, it crashes sonar often. bounce the track or freeze it as soon as you're done with it.
 
from what you're saying I think you should be using z3ta instead of rapture psyn and pentagon. if you need step modulation, sonar's step sequencer does the job perfectly. better in fact than the stepper in most of my synths. actually if it's really important to you, you should look into NI Massive.
 
 

scook
Pentagon is no longer bundled with SONAR so updates are unlikely for it.

what about the others? z3ta2 is probably the most recent, most are ancient in software terms... fwiw, i'm not sure why they're even included these days

Am I fool to think Rapture is awesome?

gswitz
Am I fool to think Rapture is awesome?

IMO... nope.      I like and still use Rapture, DimPro and Z3TA.   Not necessarily in every project mind you, that role is pretty much reserved for Kontakt, but often enough that I'd miss them if they weren't there!
 
CW definitely can't win with this one though, since there will always be those shouting "no more plugins!" and those wanting the plugins to be updated/changed.   What to do, what to do...  
 

Part of the plugin backlash was that it felt they were including things just to pad spec lists.   They had a lot of entry level plugins from Kinetic and P5 that got dumped into Sonar.  For example, of the P5 effects added, only Alias Factor really added something new.  
 
The other issue is that Sonar has a user base which is more based towards guitar based music ("3/4 of all of our employees play guitar"), and plugins like PSYN, the Roland Groove Synth, Beatscape, and RXP don't really appeal to that crowd.
 
Getting back to the synths...
Rapture - clearly my favorite of the lot.
 
Dim Pro - I find that it has a nice palette of sounds with low memory footprint.  Before I got Kontakt, it appeared on every track.
 
Z3ta+ - I have had more bugs with the "classic" version than I ever had with Pentagon, but the new version has been perfectly stable.  I respect what it can do but I sometimes find it frustrating.
 
Pentagon - See my thoughts in the thread below:
http://forum.cakewalk.com/Pentagon-m3153474.aspx
 
PSYN II - This sits in a weird space between Pentagon and Z3ta.  It's not one of my favorites, but it does make some good FM bass sounds.  Some of the organ sounds are surprisingly good too.
 
TTS-1 - I have never used this in a finished project, but, I find it invaluable because sometimes you just need a basic GM module.  This one sounds a lot better than the old Roland VSC that was included on earlier versions of Sonar.  All it (and Groove Synth) needs is a better menu for navigating patches.