Are MOS's such as 19D, 68W, 11B, or 31K good jobs for someone looking to make the Army a career?

So you're looking to make this a career, you have to define success for yourself first. If you see that as making rank as quick and as much as you can then combat arms is culturally the better route. If you want to leave the Army with a diverse resume then medical is good. I can say that once your in the senior ranks that you can hold a large degree of different jobs as a MSG or SFC. Take varies schools and get management time, it doesn't have to be leadership time. Just insure you're managing something as a project, warehouse, or large numbers of people. This can pay big money once your done, if it's big money that drives you.
Overall just enjoy the work you do and take care of your mind and body, you'll want those when you leave service.

68W has unlimited potential, you just have to seek it.

I am a 19Z (19D) for 26+ years and enjoyed every minute of it, my first six and a half years was Air Cav, then BFV Master Gunner. Do all over again.