The absolute last thing sonar needs for electronic music is more instruments and audio content. What it needs is duplicate, an automation envelope system that isn't geriatric, and to be able to record soft synths in real-time. All three of these are in the feedback forum right now, I welcome you to give the posts 5 stars.
"world-class" producers don't use any synths that are included in any daw, they use Massive, Nexus, Alchemy, SynthMaster, FM8 and Sylenth. Quite a few of them use Z3ta+ however (it was recently recommended by none other than synthesis god BT in an interview). I don't think there is anything you can do in psyn or pentagon that you can't in z3ta+, so why bother to update these dinosaurs? There's also Rapture, anyway. As for Dim Pro, it's a rompler for old school sounds. Some people prefer making good 90s or 80s music than that ear-raping millennial ****, believe it or not. You need a better rompler: get Nexus. Which doesn't come included with any other daw, again.
If you need a better arp, get a synth with a better arp, or get Cthulhu or Kirnu Cream. There's this thing called VST support for a reason in Sonar.
Jesus H Christ, man.
If anything, I'd say dolts like you are the reason Cakewalk don't spend more time catering to the desires of the electronic music crowd. The guitar grandpas at least don't constantly talk out of their ass and **** and moan incessantly for no valid reason whatsoever.