Agree w/PapaG that this is kind of a train wreck thread, but let me see if I can add something...
I don't think anyone (seriously) is saying to dump LMA for garbage. I don't think anyone (seriously) is saying LMA's the best PF in the game when LeBron Raymone James and Carmelo Anthony are allowing their teams to play extended small-ball.
But in between those two is some pretty large gray area. One would think that if LMA was (let's say) a Top-3 PF entering his prime on a pretty reasonable salary for 2 years after this, that he'd bring back an absolutely awesome haul to us if we trade him. I'm not sure that's the case.
From almost everything that I've seen from LMA over the years (whether watching every game until January, or reading the quotes from interviews, or looking at both "normal" and "advanced" stats), he seems to fancy himself as a slightly-poor-man's Dirk. Aside from the random LaMonster stretch every now and then, he hasn't played anywhere near the level he was in 2010 where 11% of his game was tips/dunks/inside 3 feet and 36% was inside 12 feet. He's now shooting 74% of his shots from outside 12 feet, at a 42% clip, a career-worst. (To put it in perspective, Lillard shoots 76% of his shots from outside 12 feet, but since he's making 36% of his 3's then his TS% is higher than LMAs). His offensive rebounding rate is 12% lower than his previous career-worst (7.1% to 8.1%). One might assume that having Hickson acting like a rebounding beast is stealing some of his opportunities, but JJ's ORB% is lower than Oden's and Przybilla's were in years when LMA was consistently getting 9% and 10% orb%. His DRB%, however, is the highest it's been in his career. On average (PER, Rebounding, TS%), he's playing at about the level he was in 2008-09 (except with a much higher Usage Rate and a much lower ORtg), where he wasn't close to being an All-Star, he wasn't close to being the Lead Dog and it was thought that, with some work, he could make the leap.
The question becomes: What does the team do now? If LMA goes back to being the LaMonster from about All-Star Break 2011 to All-Star Break 2012, playing what is in effect the C position on the block and defending opponent Cs, he's an underpaid All-NBA force that you have to keep. Even in a regression year for him this year, his PERdifferential at each position is +2.5 at PF (the bulk of his 2000 minutes), but +14.4 in his 250 minutes at C. He destroys other centers when he plays there.
But when he's doing his Dirk impression (and not nearly as well), a large part of his effectiveness goes by the wayside (and you're seeing it this season). Unfortunately, I don't think it's an isolated thing:
Aldridge addressed his more perimeter-based game earlier in November to Ben Golliver: “With Nate [McMillan] it was more of me on the block all game, all day. People got used to seeing me in that light. The team was easier to scheme against. Now we have more movement. When asked if that makes him more of a finesse player, he replied that “I think people take my game as finesse but they don't see me banging Chuck Hayes six times to get to that spot and then shoot it. People just see my jumpshots, they don't see what I'm doing to get to my spots.” As a non-coach I don’t know how banging with Chuck Hayes to get to a jumpshooting position is better or worse for movement than banging with Chuck Hayes to get on the block, but I do know that the efficiency of the shot—and therefore the offense—is significantly better with him shooting from the block rather than outside. Dirk Nowitzki (who Coach Stotts may be profiling Aldridge as?) shoots a similar split of long jumpers, but is consistently in the 48%-to-54% range, including enough 3-point makes to boost his True Shooting Percentage to the high-50s to low-60s percent. Last year Aldridge, for the first time, had a mark above 55%, and has regressed to 52% this year.
For me, it's difficult to place LMA in the "untradeable" category that I'd put Lillard in. In looking at this team going forward, I think (along with a lot of people) that, whether or not LMA is kept at the PF spot, a defensively-capable big man is needed. (It's a bit amusing to me, since LMA was drafted as a DPoY center to go next to Z-bo, how things have changed). We've talked ad nauseum about how, in the eyes of most, JJ and LMA as our two starters going forward (at whatever the price) probably isn't a contender for much. So, imho, it's worth looking at what a "multiple-all-star-maybe-top-3-PF-in-the-game-with-2-years-left-on-a-pretty-good-deal" will bring back that can fit our team going forward. If the verdict is that he somehow doesn't bring back a good, young-ish defensive big and some other talent (either young guys who haven't played much or potentially good draft picks), then keep him and roll the dice that he plays more like LaMonster than LaMarshmallow. But if you can get your defensive big of the now coupled with some more assets while clearing even more cap room, then I think you have to look at it.
And I don't want to bring up Batum much in an LMA thread, but for those who don't like his play right now, do you think he forgot how after his triple-double streak? That other teams scouted him harder? Or maybe that when you can't shoot, pass or dribble without pain in your severely sprained (broken?) wrist that it just may impact your game? Honestly, I think that it's more an indictment of our bench that a hobbled Batum is still the best option to start and play 35mpg.