Maybe this was discussed earlier, excuse me in advance.
Actually, the question is - why Dimension Pro are more expensive (or for the same price) than Rapture, despite the fact that (In my quick look) Rapture has a more advanced capability (multi,detune,ringmod functions in osc section at least)
What original in DimPro (versus Rapture)?
Or because of the content size in the main?

Different type of synth. Rapture compares a little more easier to Z3ta+. With Romplers it is all about the massive sample library.  Dimension can do things that Rapture cannot do.  Once could  (in theory at least ) play every part of an orchestra with DP.  One could come closer to making Rapture type sounds with DP than Rapture could come to making acoustic instrument sounds like DP.  Still not a fair comparison but if you had to create music in many genres from hip-hop to classical and could use one synth, you would stand a better chance with DP than Rapture.  With that said, Rapture is clearly superior when it comes to synth type sounds and for some that may represent a better value than DP. 

I'm sorry, my imperfect knowledge of the English.
But I would like to see presence of specific differences, technical details so to speak.
If you mean the difference based on the stylistic direction, then this is in my opinion not enough to call them types are different.

Everything that comes to my mind from the technical benefits in DP, it is a some tags "Physical Modeling" or "Wave Guide", It seems Rapture is devoid of this.
But what exactly are is these DP features and what their potential is, I'm not versed yet (not felt yet).

Rapture uses short, simple samples - organs, waves.
 
DimPro's library is a more extensive, acoustic range.  Longer samples and many more of them.  It costs money to record a sound library. 
 
Rapture's engine, as you've noticed, is stripped down from DimPro (which came out first).  Also, I think Rapture turns all samples into wavetables (not the ppg kind but a sample of the sample in 3000 cycles).  DimPro is a sampler for any "file" over 3000 samples long.  So rather than just playing organ or synth ocsillator waves, it can playback longer acoustic files.
 
@

Thanks for some info.
(Will also need to dig into the manual.)

Dim Pro came with 7 gig of samples. Raptures only +200mb.