Suns without Nash are without a doubt still a playoff team, even in the west.
C - Amare: one of the best young big men in the league,
PF - Marion: one of the best role-players in the league, 20/10 guy his whole career, can do almost everything, great defender
SF - Diaw: currently the best Point Forward in the league, also a good defender
SG - Bell: great defender and 3 point shooter
PG - Barbosa: not a great floor general, but is a great shooter and slasher, also a decent defender. Better than many starting PGs in the league.
They'd have to play half-court ball probably, but with that talent they are still a 50 win team.
That's no slight against Nash; team success is completely overrated in determining the MVP. Jordan-less Bulls in 94 still won 55 games, doesn't make MJ any worse.