Take the risk with his bad shot selection? That's equivalent to playing Russian roulette with six rounds. Trust me, you don't want none of that. D'Antoni's offense will just give him more situations to put up shyt from 16-ft out. Teams will just beg him to shoot off the PNP/PNR and they'll stay deeper in the paint when they see him with the ball - low% chance (compared to Pau) they fall for p-fakes to draw them out. Yes, his athleticism will enable him to captalize on more drives to the hole than Gasol - but not to the point where it will outweigh Pau's production-ability = ability to hit from the outside or re-set with Nash or make a play for x-player; things which Smith is damn near incapable of doing. Plus you've got the whole free throw situation as well, having Smith and Howard at the line in close games (which will be inevitable in the playoffs) is heart attack material; the chances of BOTH of them hitting FTs (in a game) to a beneficiary-level for the Lakers is too low to even think about.
It's really no use moving Gasol now. This team's window is this season and this season only; moving him for Smith would just be counter-productive. Pau knows what it takes to get the job done, not saying he'll get it done but this team doesn't have time to be mixing and matching 'big pieces' in hopes for a remedy, that they might not even need.
Lakers have more of a chance winning a ship this season with Pau then they do with Smith. That I'm sure of.