If you put Angeli behind a stout pass blocking OL where he could use his mobility selectively instead of out of necessity then I think he'd be great.
Angeli is the better passer and when given time I think he's the better QB, but in the limited exposure we've had Angeli decision making falls off quickly when pressured (which is likely more about experience than ability). The problem is we don't have a stout pass blocking OL, so despite his obvious deficiencies RL may be the best guy for what we're currently dealing with.
Having said that, in the next game RL is struggling and we're in danger of losing I think you HAVE to give Angeli a go.