I think dwight is a risk, but I also think trading pau for iggy is a risk. Bynum is a better 1 on 1 player than dwight, but with Nash, Im not sure that matters as much. I still think dwight would help fix the laker's other weakness, pick and roll defense, and as long as you're not giving up pau and bynum it's worth it.
As far as grant hill goes, I dont see why signing grant hill means anything as far as Metta goes. The lakers have like zero bench right now, and adding grant hill with a vet min contract to bolster the bench seems a no brainer. (I dont think you sign Hill to relegate Ron to bench duties— Artest is a good piece in between 4 talented players, but leading the bench unit? Probably a catastrophe.)