Yes, I prefer the one piece line, less possible leak points and possibly a better "feel" because of the elimination of the junction block. The two piece original set-up was to allow for adding a second line (and disc) if you wanted. It was an option here in the States but was standard on some of the European 650s. Honestly, this bike doesn't need that second disc. The single disc, if operating as it should, is good enough.
Cleaning is pretty straight forward. You can use that spray brake cleaner on all the parts once disassembled. You may need to do a little gentle scraping to remove built up crust. The little wire wheels for a Dremel are good for cleaning corrosion off the parts. In the caliper, the important item to get cleaned out is the groove that the large main square-sided O-ring seal fits into. Over time, brake fluid gets in there and dries up. It forms a crust in the groove. This eventually forces the seal out more and makes the piston stick. So, clean all the parts real well, lube with fresh brake fluid and re-assemble. If the system isn't leaking anywhere now, and you're careful not to damage any of the rubber parts during cleaning, you shouldn't need to replace any of them.
