along the lines of the OP, if you have been out of 121 flying for a long time, I think it would not be a good idea to take a DEC in anything. Even a plane you flew 10 years ago. I remember back when I upgraded at a regional. I had a lot of time in the plane as an FO, I upgraded in the same plane in the same domicile and hub system. Flying the plane was the easy part, everything was familiar. But being the PIC , especially at a regional puts everything on you. Where I worked, the dispatchers were not experienced, the station managers, rampers, etc were mostly college kids working part time. You had to watch everything, because when the s*&^ hits the fans, it all comes down on the CA. I had dispatcher try to send me out with one way fuel, to and airport with no fuel!!. Give me a release to a closed airport, etc.
before 911 I trained at a major where they put new hires with CAs that were upgrading to the plane. Even though many of these guys never flew an Airbus I could see training was easier for them because all the company procedures and op specs etc, where second nature to them, where as it was all new to me.
We all know regional training is minimal at best. I think it would be much less stressful if you started out as an FO, learned the airplane, the company procedures and the system they fly in,etc, get a few months under you belt and then upgrade.