Is Trimble a good choice for backup PG? In a vacuum, sure.
I have high hopes for Trimble but, to me, the question isn't whether he can do a good job at backing up at PG - it's whose minutes is he taking? In other words, if RJ is the guy who backs up at point, which other teammate gets to play more?
At first blush, if RJ backs up at PG for, say, 12 minutes per game, that's 12 minutes that Ryan or Wilcher could be playing at SG.
So the real question is whether you'd rather have 12 minutes of Ryan (or Wilcher) or 12 minutes of Trimble.
Another way to think about it is whether a Trimble-RJ backcourt is better or a RJ-Ryan backcourt is better. Which would you rather have on the floor. I'm going with RJ-Ryan. Or if that doesn't work for some reason, I'll take RJ-Wilcher.
Unless Trimble has improved a good bit, I think 12 more minutes of Ryan probably makes a better team. Unless maybe we need D at that moment, in which case Trimble could be the better choice.
Very good question, thought provoking, that is what I like! You have seen me say on multiple occasions, it is my sincere wish that I have seen the last of RJ at the point, to the same level that I am glad to no longer have to endure watching Nance as a stretch 4 or Leaky Black as a jump shooter!
Now when Cadeau sits I want Seth to back him up, but a bunch of reasons but for this I will limit it to just 3 major reasons.
1) With both Cadeau and RJ starting, when Cadeau sits I want fresh legs at the point and that means I want either Seth or Wilcher to take the point, love Wilcher's decision making, defense, and how hard he plays, all with a really good bball IQ, I think he has that pass first mindset I want my PG to have. I think Seth has all of that as well and he isn't a freshman, I like Wilcher more as a 2 than I do Seth (I think Wilcher jump shoots a little better than Seth). I want speed and quickness, ball handling ability, wrapped together with a high basketball IQ at the point, that is of course Cadeau but I think it is Seth as well. Example, very clearly now that Cadeau is set to play for us next season, he is by far the quickest and fastest guy with the ball we will have but in my view right behind him is Seth. Those 2 are my PGs, no questions asked.
2) Fast breaks...pretty much been MIA for the last 2 seasons, have watched far to often yet another UNC break called off and here we go right back in to pounding the ball east and west for the next 20 seconds until someone named Caleb has to take yet another long hard well guarded prayer from 40' out. You are not going to be able to keep Cadeau from pushing the BREAKS any more than it seems Hubert was able to stop RJ from pushing the BRAKES (see what I did there with the spelling of breaks). But the breaking game is also what Trimble wants to play in where he can use his crazy athletism quickness and speed to either finish above the rim or slip it to a trailer, or push it and be the trailer that slashes off the return pass. It was if we kept a governor on the kid last season, RJ had the ball and called off the breaks where Seth would have finished them.
3) Just simple PG basketball IQ, being aggressive but being smart in your decisions, and realize you are running the team, it is your responsibility to get your mates involved even if it reduces your own scoring looks. Simply put, when RJ drove he was pretty much exclusively looking to finish himself, when Seth drove his first thought was to draw and set up a pass to a open teammate. Seth is a North to South player, he is not about east and west, RJ as a PG was far to much east west wasting seconds on the shot clock. That is not a ding on RJ BTW, it is just ingrained in how a kid plays, RJ just has always been a go to scorer and I don't know that he can or even should change that, it is a great mindset for a 2 guard, it isn't the best thing for a PG in my opinion.
Now I do admit to one concern, I don't know if we are better with RJ or Ryan at the 2, I mean we all know that RJ is now our starting 2, no mystery left about that, but should that be the case is a different thing. Ryan will play and as does most every season, things will sort themselves out even if it takes a player having to leave the team to go be with a "sick family member" (did ya get my snide Garcia reference, if not it was there in plain sight ;-).
Oh and you asked which one of those back courts I liked more, I think I like the Trimble/Ryan back court slightly more (note Cadeau was not listed in the back courts choices that I am responding to). I do because I think Seth would set Ryan up for better looks than he would get from RJ. I believe Ryan was a 40% 3pt shooter when he had a PG that got him cleaner looks than he got last season. But let me add, RJ was a much better shooter last season when he didn't have his fingers wrapped due to sprains, believe AJ shared that RJ was a near 50% 3pt shooter last season when his fingers were not wrapped, so do consider that.