Hah yes, i only wish i understood more about the chemistry of the brain and the effects of SSRIs, but my only experience is its use, not the science behind it.
I would have to agree with you with the shorter but more "real" REM periods. This is possibly why it becomes so hard to interpret my dreams on the higher doses, as my brain is trying to fit the same amount of information with a lot less time, causing my dreams to be vivid and extremely emotional.