First of all, their web browser is terrible. It really doesn't even classify as a modern web browser. Probably 80 to 90% of the sites I frequent are basically unusable on it. Opera isn't much better. Too slow & buggy. I haven't used any of their newest models but it doesn't sound like they've made any massive improvements. Even if they do there is a considerable perception problem to deal with. There are ALOT of BBs out there and probably 99% of them have awful web browsers. Even if they were to release something now that was very good it would be an uphill battle. Mobile web is now the real killer app for smart phones. RIM is years behind.
Second, they've really fallen behind on e-mail. Setting up a BES server for Exchange support is weak. It needs to be built into the phone's mail client. Attachment viewing is clunky at best. Needs to support more file types and do a much better job supporting existing file types.
Third, no wifi? That would have been understandable in 1998 maybe. In the year 2008 not having wifi as a standard feature is basically suicidal.
Fourth, they seem to be fragmenting their market. 100% touch vs. touch + keyboard, no touch, flip phones(??) QWERTY vs. non-QWERTY. Different screen sizes/resolutions. Not a good idea.
My suggestion to RIM is to just give up and adopt Android. History has shown (in the case of Palm, Windows Mobile) that once you fall behind it's very hard to ever catch-up. Even if you do catch-up technically you're fighting perception vs. reality. You can have the best current-gen product out there but people will always judge your products by whatever model they have used in the past. It's not really fair but that's just how it goes. A big move to a new platform at least draws a clear line in the sand to differentiate your new product line.
Since Android's SDK is all Java based porting apps would be pretty easy. Although there's really no single BBOS app I can think of that I would actually want to see ported. Even the most basic apps are in need of a major GUI overhaul anyway. They'd probably be better off just adopting the standard Android apps.
I don't think RIM has to worry about becoming "just another Android phone maker" because they do make some of the best phone hardware out there. They're going to have a big advantage over the competition. They have more brand recognition too -- it may be a little tarnished but it's not too late to save it. The key is not holding onto the past until the hole is too deep.