BlackBerrys are not for everyone.
Do I think they could do better? Sure. Should they try to go head to head with other consumer handsets? That is what they appear to be doing with the Storm and look how well that worked out so far.
The core issue with BBs, in my opinion, is that they still must maintain a level of security that other manufacturers are not bound by. There was talk and speculation that RIM might begin producing two different OSs. One that will continue to meet DoD standards and be used on more basic devices and a new OS that could compete with the iToys of the world.
In my opinion, trying to be all things to all people will be the kiss of death for BlackBerry. Their success began as a very secure platform accepted by governments, corporations and the like. The fact they have been able to adapt to a broad range of consumers, but still maintain the core of what they are is no small feat, but there has to be limits.
I am not a programmer and certainly not a computer engineer so maybe I am all wet in what I am saying, but I do believe there are limits to what RIM can do with the basic OS and the RIM servers everything is funneled through.
While many people have "discovered" BlackBerry I think there is a certain percentage of recent converts who will move away from the BB platform simply because it isn't cool and new anymore. Once the Hollywood types were seen with BBs that is what help the growth to explode. Sad that a manufacturer's fortunes are tied to being seen in the hands of a "star", but it is what our society does. When the "stars" move on, which they will because another manufacturer will offer them billions to endorse their product, the followers will quickly move on too.
Of the groups that convert and move on to the next big thing there will be a number who realize that the BB is their chosen device and will remain. They tell two friends, and they tell two friends, and so on. BB growth will be back to what used to be normal, slow and steady. I don't know what RIM's business model and projections are and only they know where they need to be in order to remain a viable business entity.
BB should continue to explore new functions and features, but that should not become the primary objective and if it does, they will no longer be BlackBerry.
I hope it works out well for them and I also hope that they are able to work out some of the quirks that BBs have. It will be interesting to see where they will be five years from now.
Enough of my pontificating....