I don't think Trent can 'replace' CJ....but I do think he could do a more than adequate job filling in for him on offense, and of course would be much better on defense.
ADD to that, what we could get for CJ and combine it to what Trent could provide, and I think it would out-weigh in total, what CJ and Trent off the bench provide now.
That makes sense, except a lot of the trades people suggest around here involving CJ undersell what we'd get back, so we aren't acquiring a player that could offset his loss, even if you think Trent reaches his absolute positive in potential.
What CJ does that is very hard to quantify is he can break down good defenders on his own and create shots for himself or for teammates ... and I'm not just saying about his passing, but he just by drawing help defense he creates opportunities for offensive rebounds and uncontested buckets at the rim that might as well be assists.
He also has shown an ability to rise to the occasion and isn't shy about taking big shots ... and making them.
Finally, his ability to be a second point guard takes pressure off Dame by allowing him to bring the ball up the floor and start the offense even against solid defense. I'm not sure you're going to get that from Trent and you definitely aren't going to get that from a player like Ant at this point.
So, you need to acquire a 3 with an above-average handle (say like a Nic Batum in his prime, at the very least) who can create his own shot when the play breaks down and likes to have the spotlight in key situations. Either than or they have to be incredibly efficient on offense and a demon on defense. That's the only way, IMO, Trent and whoever the Blazers acquire in a hypothetical CJ trade offsets dealing away CJ, and, like I said, so many people are eager to get McCollum off the team, they are taking any slightly above-average player back thinking it would be an improvement. It wouldn't.