do you think Jennings is better than Trey, in general?
Yes, but I am not sure that will be the case in several years time. I think Trey can be a very good second option for us, if, of course, he is willing to play that role.
do you think Jennings is better than Trey in Q's system? (recognizing, of course, that it is less position-focused than other systems)
I think neither is ideal, since both seem to be ball-dominant and Trey's instinct is to pound the ball and look for his shot. But Trey have flashed some great facilitator moments this season. I think he's better(more willing) facilitator in the pick and roll. On the other hand Jennings is probably the faster playing PG, which would probably help with pace. Jennings' shot selection is about as horrific as you can get in the league right now, but he also drives and draws more fouls. In general I'd say it's very close as to who's the better fit.
Your post is seems to imply that any deal for Jennings would be a bad one. There are, of course, bad scenarios. Are there good ones, too?
I wouldn't say any deal would be bad, but in general at our current level of rebuild I don't see why we should go for it. Unless we are desperate to improve by 2-3-4 wins this season(which of course would harm our draft position as well) I really don't see much sense in giving up assets(first round picks) to get him. We have to keep in mind exactly what kind of player he is and what his ceiling is(whatever player he is right now is about his ceiling). I think he's a bottom 5 starting PG in the league.
In general I see him as a liability in our current situation - he's good enough to harm our draft positions next year, but not good enough to start for us in the long-term, also he's not likely to improve much. He also comes with a 8 million dollar tag, which for a long-term bench player(if we assume Exum will be our first option) is very very steep price. We are in a small market that can't really afford to pay a long-term backup PG 10-12% of our salary cap... His contract expires in 2 years so I guess that can be looked as a positive(we don't have to get tied with his contract for too long)... but see... this is exactly what I am talking about - every time I start talking about contracts with the feeling and sentiment that they are burdens, I worry. Every time I start looking at the length of the contract and feel relieved when I see it's short, I can't help but think that this is a liability contract that we should never give up assets for. If anything we should be getting some asset back(say second-rounder).
I don't know if I answered your question. In general I'd see a trade for Jennings as good, if we get some value long-term(or asset wise) in return, or if we shed off some of our own liabilities(we don't have any really right now - if Burks doesn't pan out he's as close of a liability as we have).