I'm sorry, but I think most of this is just excuses cuz we dont want to admit it was a mistake. Hindsight is 20/20, but for right now, it's looking like a huge mistake.
1. Brooks is getting a lot of time, because when he was given just a little time, he did a lot with it. He is being asked to score, but saying he's "scoring without conscience" doesnt make sense if you watch him play. He is scoring within the offense (what little they have). With the weapons he's shown (midrange, hesitation dribbles, floaters in the lane, 3pt range, etc), he could score 30 if he wanted to play "without conscience". He is playing confident, but he isnt forcing anything.
2. Brooks isnt a bad defender. That would be an easy thing to point to, as an excuse for why Doc wouldnt play him...but its just not true. If all you see is his boxscore stats, you might think that, but he's not a bad defender. On the other side, everyone assumes JJJ will be a good defender, but thats no guarantee. In college he played against weaker competition, and has a size advantage that is gone now that he's in the league.
3. Saying it's easier on Brooks because of his position, doesnt make sense. Its a guards league right now. All the elite players are at the wings. Thats who Brooks competes with every night. A half decent big would find it easier to have success in todays NBA, than a good wing player. There's no reason a pf should be "expected" to accumulate more fouls than a wing...especially if playing against lesser players every night. Just playing the PF position doesnt mean you automatically have greater defensive responsibility. Most teams play man...thats a 1-on-1 responsibility for everyone. Maybe a Center that anchors the defense like Chandler/Perk/Bynum has a greater responsiblity, but a PF known for playing away from the basket like JJJ would never have any extra defensive responsibility.
The main reason Brooks is excelling and JJJ has yet to play, is that Brooks already has the physical gifts and skills to beat his peers, and JJJ doesnt. JJJ has a great handle and shot for a PF, but he seems to be too weak. At SF, he'd have a size or strength advantage, but questionable dribble and speed. Until either his stature or skill set develops to the point where he can fulfill all the requirements of a position, Brooks will be superior.
No matter how many minutes they both got, Brooks would come out on top this year. It was easy to criticize his game when he was just scoring on bad teams, but he did the exact same thing to use. Unless you want to say that we're an equally weak defensive team to those he played before, I think he should be given his due credit. So far, I think he's competing with Ricky Rubio for ROY
The one thing you've overlooked is that JJJ is behind KG and Bass on the depth chart. He'd have to beat a HOF player and a top candidate for 6th man of the year to get on the court. If he played any other position on this team he'd have a chance to at least compete for time against a vet bench player that's certainly 'upgradeable'.
If we had kept Brooks, his competition would be Bradley and Moore, not exactly stiff competition there. Too early to be evaluating this trade as a bust.
And this is why I think this trade was a mistake from the beginning.
Even if we did not have Bass, JJJ would still need to play behind KG and Baby and for that matter, Wilcox. With only Bradley and Sasha, we have no wing depth that is productive. Brooks, with our championship window really small, could've helped us NOW.
With his ability to create and make shots for his own, it can give Ray and Paul some breathers and we will not miss anything on scoring. If he can play against the first units, he may very well beat 2nd units. He could give us 10-14ppg off the bench in 20 minutes no problem.
Everybody says Doc doesn't play rookies, I bet he will play MarShon with his skills and what he can do.
And as to he can't defend, I don't know, I think has the stuff to become a solid defender with the right coaching.
I'm not throwing JJJ out, I just think this is a mistake.