What you're describing is a chicken and an egg problem.
"They have/had great smartphone features, particularly around messaging, and they have server software running in most corporations around the world." -- They had to build an OS from the ground up BECAUSE they value these things. Android is great for what it does, but security is not one of it's strong points. Blackberry's name is built on security for those messages.
You can't just throw that out and still have a Blackberry. If they were shooting for another consumer reskin, then they could have waded into the bloody waters of the Android market and sold themselves to the highest bidder. Instead they took the hard road, bought a rock solid kernel and built a new OS from the ground up with messaging, security and the future in mind.
iOS and Android are great, but they're starting to get long in the tooth. They ride the cutting edge, but eventually that will show it's age. Blackberry started over the beginning to build an OS for the next 10 years. If they can launch Mobile Computing, it's a bright future.
That, however, is a BIG if.