I agree, I'd prefer a longer ride with the sensation of speed, then have that actual speed and the ride being over in a minute, plus the ride needs to operate in the rain, and that hitting your face at 88mph isn't pleasant.
Would still be fun if the ride was only about trying to get to 88mph but failing, would explain the whole roll back looking section and multiple launches. Actually hitting 88mph and traveling in time also wouldn't really work thematically, even if they themed the unloading area as 2015/1960, which would be cool, you would still walk out to what I presume is 80's Hill Valley, unless I can buy a Pepsi Perfect, whats the point!