You guys really don't think "Sensitivity" is a classic?
Timing is everything, especially back then when every genre of music was a bloodsport. Ralph was clearly meant to be the breakout star of New Edition, the next Michael Jackson. His album would have been a big hit if it came out in 1986/1987 like it was supposed to. Remember, Bobby's debut wasn't Don't Be Cruel. It came out around that same time and it flopped.
But then the label delayed it and Ralph decided to stay with New Edition. And we know what happened next. By the time Ralph came out with his debut, the R&B genre had changed completely and there was no window for him to be the star he could have been. There was too much competition, his own group mates were killing it with their music. It just wasn't going to work.
The same thing happened to Bobby. Don't Be Cruel was a monster album, and his follow-up could have been huge also, but it came out five years later. Sometimes, it even happened to artists who just had success. DJ Jazzy Jeff and The Fresh Prince had a multi-platinum, Grammy-winning album. A year later, they couldn't even book shows anymore and were going broke because their next album barely sold anything. Staying hot back then wasn't easy at all.