I only compared Walker to Smith in terms of shot selection and I suggested Walker's would be "less infuriating". Along that axis, I think it is a fair comparison. Hollinger's stats rank him as 66th amonng power forwards in true shooting percentage this season.
As for power forwards better than Smith right now, I would say (not in this order) Kevin Love, Pau Gasol, Ryan Anderson, LaMarcus Aldridge, Blake Griffin, Chris Bosh and Dirk Notwitzki. Kevin Garnett if you consider him as a PF playing out of position. Tim Duncan perhaps. Cases could be made for Paul Millsap, Zach Randolph (if healthy), Carlos Boozer, and Serge Ibaka. The folks at Wages of Win would probably say Kenneth Faried is better, but I'm not sure I would go that far.
So, I'd say no better than 8th and it would be reasonable to leave him out of your top ten.