Application switching has been a feature of the blackberry for ages, it was a hidden shortcut orginally and is now both a shortcut and a menu option nowadays.
Corrective typing - the blackberry already has some stuff like this on pearl and storm devices and presumably it is something they will improve still further in future products.
Gesture support - now personally I have never been a big fan of this stuff in programs or devices, but I can see its benefits and you would hope that rim will also introduce something along these lines to take advantage of the touchscreen, but equally this is simply a feature enhancement rather than a need to throw out their existing OS.
Developer connection - I think you have missed the crucial point about the success of apps on the iphone, they have not done well because of the "sexiness of a NEW OS" at all, they have done well because apple provided good support and more crucially a very good means of delivery.
Rim have been reasonably good at supporting developers in the past, but need to expand that support still further to also get the hobbyist coders involved as well because even if a lot more crappy apps will be developed you will also end up with those gems that you couldn't do without too.
However, without a centralised portal for easy access to applications it won't actually matter how many people start to develop for blackberries and it remains to be seen if the app store can be improved to the level it needs to be, as you say only accepting paypal is terrible move, ideally they would have their own payment processing system, but at the very least they should offer multiple payment options besides the dreadful paypal. The general usability of the app store needs to improve as well, but then again its not even available worldwide yet, so it's still a work in progress.
The BB may be your round wheel - without room for improvement - but to many others, the BB OS is a flat tire that does not have the capabilities of the new kids on the block.
Where do I say or imply there isn't room for improvement, there are clear areas to improve and nobody would argue with that, my argument is with those who think that the only way things could improve is if they throw all the existing stuff and start from scratch because that can also lose you the loyalty of your existing customers.
Just look at some of the additions that apple made in their last updates, they were quite clearly aimed at the business sector and I am sure they would be delighted to hear if Rim took their eyes of that market to chase others.
If Rim is to keep expanding then they need to bring out new hardware and improved software that appeals to their existing customers while also appealing to the customers of their rivals (symbian is still the world leader even if it is steadily losing market share) and also to appeal to people moving into the smartphone market who had previously bought ordinary mobiles instead and they don't need to throw away what they have to do this.