My god, no. You are using the general argument instead of the rationale behind it.
The Spurs fans decry the Suns method of play not because they play run 'n gun, but because they play NO DEFENSE in the process.
This is laughable because not only does it take away from their run 'n gun style of play that gets them a lot of their wins, it also takes away their most versatile defender, the ONLY one who can even hope to contain Parker and Manu (they both mismatch on Bell, Parker is too fast, and he can't really effectively contain Manu), AND it reduces depth by eliminating a guy that can play the 1-4 positions whenever they need, replacing him with a 5 only.
If the Suns traded away Marion for Delambert + pieces, or a big guy with a proven defensive record, it would be understandable.
If the Suns slowed their game down by dumping Amare to big up a guy who gets blocks but not as many touches, I would be a lot more concerned.
So what did they do? They traded one of the most versatile men in the league, the ONLY man who have EVER, EVER, EVER shown one iota of an ability to slow the Spurs attack down, for an injured, out of shape, broken down shadow of his former self, who now draws as many fouls as he does rebounds. He will be absolutely the worst "good" big man in the league at rotating over to stop Parker and Manu without fouling them. And he chokes their offense in the process. Not only will they not have Marion to create fast-break points and make defensive plays for transistion offense, but now Amare will not have the spacing he is used to being granted in the post to do his thing. Instead of his little jump-hop-dunk, he'll be jump-hop-be-double teamed by the guy sitting on Shaq watching him pant and wheeze under the hoop.