I have had DMs use old PC's on occasion and have run into what was feared the most...the rest of us being observers or henchmen to the guy.
I have used my PC's as NPC's, but I try to have a good reason for it or a good story hook. Currently I'm doing it right now. The NPC had buddied up with the PC"s and journeyed to the same place for them to be separated in combat and the NPC taken prisoner. Really it was up for the others to decide to help the guy or go on thier own merry way.
More often than not if I usually have a chance to play I find myself choosing to play an old NPC as a PC instead. By then They're usually pretty fleshed out with a personality and background.
I have used my PC's as NPC's, but I try to have a good reason for it or a good story hook. Currently I'm doing it right now. The NPC had buddied up with the PC"s and journeyed to the same place for them to be separated in combat and the NPC taken prisoner. Really it was up for the others to decide to help the guy or go on thier own merry way.
More often than not if I usually have a chance to play I find myself choosing to play an old NPC as a PC instead. By then They're usually pretty fleshed out with a personality and background.