those rankings you listed are on a per basis. Looking closer at the numbers is a bit more revealing as well.
Portland's SG position ranks 1st in the league in assists and 2nd in free throw attempts. It's certainly a tribute to Roy's ability, although I'd say Jack would get some credit for those rankings as well. Of course, it's certainly Jack that's primarily responsible for the 26th ranking in turnovers.
We know PG is one of portland's weaknesses, and those numbers do verify it as you said. 28th in points, 27th in rebounds, and 24th in FTA. Ouch. PG doesn't rank in the top half of any category for portland. That's the only position where that happens. All other positions rank in the top half in at least 2 categories.
At C, portland ranks 6th in rebounding. Joel and Channing deserve some credit for that.
The SF position is interesting. The blazers rank 4th in both FG% and 4th in turnovers. On the other hand, portland's SF's rank 27th in rebounding and 28th in assists. Those are the 2 major problem areas at SF for portland.
If you go to the team production page:
http://www.82games.com/0708/0708POR5.HTM
there are some numbers on defense, and net production versus opponents by position. Those are very interesting numbers.
Again, those numbers show that portland is very strong at SG. The net per at SG for portland is +3.8. The other position where portland has an advantage is PF with a +1.7 per.
Once again though, PG is a glaring weakness with a -4.6 per.
To me, one of the most revealing stats there is iFG%. That represents the percentage of shots taken from inside/close to the hoop. Portland has a negative net there at every position although SG and C or only -1.0.
However, both forward postions are terrible in that ranking. Portland's SF's only take 15% of their shots inside compared to their opponents SF's at 31%. And blazer PF's take 24% of shots inside while their counterparts take 40%. Obviously, PF is skewed a bit because of travis outlaw's game and to a lesser extent Frye's game. And lately LMA has been making a concerted effort to rectify that.
Still, it would appear a glaring weakness at PF/SF for the blazers is from where on the floor they take shots.