As a PT devotee, I think if you feel the need to upgrade from your current setup is there, then digi002 is right for you. You say you have decent mic pre's, mic's, monitors, etc., so really the only expense you're encountering in this upgrade is that of the software/hardware, which are bundled in the 002 setup. If you intend to do your own mixing, then the 002 with the control surface is the way to go. If not, as you seem to suggest, then the 002R without the control surface is perfect for you. You'll be sufficiently compatible with larger facilities to handle your mixing for you.
Plug ins are those little third party applications that are used within PT as effects, which you have expressed concern over in this thread. There is definitely an advantage to the Mac side of this equation, as there are fewer plug ins presently available for PC based systems running digi002. However, depending on the I/O configurations of the Roland units you presently have (I'm not familiar with them), you may possibly be able to use those simply as outboard effects units that you can interface with digi002. This means that if you are happy with using the effects in these units, you can use them with your PT system as outboard effects units. You'll learn how to do this as you get deeper into learning your way around PT software and hardware. So, your concerns up front about the availability and quality of PT's effects out-of-the-box may be less substantial than you think. Again, I do not know these units, so I'm only speculating. Others may correct me here if interfacing these two systems is not possible for such purposes.
As for the learning curve, don't sweat it at all. You say you've spent the past two years learning to record. Consider this simply a continuation of that curve, not an impossibly steep mountain. I've been using PT for years now, and just learned something new in it tonight on a polka session of all things. The learning curve NEVER ends, but I personally find it to be extremely intuitive and easy to get around in (the software, that is).
Good luck in your endeavor. Hope you're finding all the info here useful. Digidesign's website is extremely helpful in becoming familiar with their line of systems. PT Free, while not something I've ever found useful in terms of realistic functionality (too much latency, extremely limited in terms of track count/ I/O options), is a great introduction to the GUI of the software and its functionality for editing and mixing. Download that and play around with some audio with it just to get a feel for how PT works. Otherwise, have no fear about jumping all the way in. You will not regret it.