I've enjoyed reading the comments on this thread, and I'm sure that the Rhino is a good gun with many merits.
The problem, as I see it, is that although the revolver (as a category of firearm) may still be very popular, it's still somewhat old school when compared to advanced modern semi-autos. Most Police officers don't carry revolvers anymore. When my friend got on with the FBI in the late 80's/early 90's, they were still issuing their agents model 13's or 19's or something. Those are and always will be beautiful guns, but they're old school when compared to the best of modern semi-autos. (I should mention, I STILL like revolvers better than semi-autos, so I'm not saying this out of personal bias.)
So your analogy may be appropriate...the Rhino may be the modern equivalent of a revolutionary advancement in crossbows, but since the crossbow is no longer the weapon of the future, the revolution isn't all that revolutionary. Now if they could make a revolver that shoots 20 rounds at a time, that would be revolutionary.
I don't dislike something just because it's different; I love old Studebaker cars, but I see the RHINO as more likely being something that's cool and unique and innovative than something that's earth-shattering.