I think I"ll be okay with RSR acceleration profile as Test Track in Epcot goes really, really fast, really quickly, at least for somebody who doesn't ride the big coasters in parks known for their thrills. They couldn't make RSR too fast as Test Track is sort of for a bit older audience, were as RSR is supposed to be more inclusive for the whole family.
I do agree that they could have made the ride longer and, IMHO, given the dark ride part more scenes. RSR has a tough job as it is judged as both a thrill ride and a dark ride.
BUT I give RSR credit for being much more than comparable E-Tickets such as BTMR. BTMR has a lot of those banked curves and dips and such, but there is no dark ride part. There is an overall theme, but I don't really associate any specific characters with BTMR, except maybe the dynamite goat. RSR is better, IMHO, as you get the feeling that you're really in Radiator Springs. I would love to have more dark ride scenes as I love Radiator Springs, but I love what is there.
Maybe we're all spoiled by Pirates with its 14 minute ride time.
I remember waiting 3 hours for Indy shortly after it opened, the line stretched all over into Frontierland, and much further when it first opened. I wouldn't wait three hours for Indy now, or even more than 30 minutes, though it is still a great ride I appreciate a little more with each visit. Radiator Springs will be a similar ride, like Indy, we will know all the ins and outs, and most of the fun will be soaking up the feel of Radiator Springs.
Also, I heard that RSR is better night, probably because you get the feeling that you might fly off the road and hit a boulder.
I also think that they should have extended the track of RSR to include an section which goes around the town (but obviously not down the main street where the guests are). Maybe the track will be extended in the future, there is a little bit of room back there.