I think Marion's length bothered Parker in the middle of the playoff series last year. By the end of the series, though, Parker had found ways to attack Marion, even if his shots didn't fall. More importantly, however, Marion's attention to Parker forced the Suns to find someone else -- usually Nash -- to send to double on Duncan. Forcing Nash to bring the double had a domino effect, in my estimation, because Duncan would find Bowen, who would force a rotation and change the matchup with Ginobili. The Spurs were able to get favorable matchups for Manu, whose offense was really the catalyst for the Spurs' wins in Games 5 and 6.
All of that is to say that Parker changes the game in this matchup by forcing the Suns into some really tough decisions about how to defend the Spurs. It may be that they think they've come up with solutions to some of those problems, and perhaps they have. My point is that I don't know that the Suns have the personnel to deal with all 3 of the Spurs biggest offensive threats without relying on some help and I think the minute that the Suns have to help, their defense is compromised.
I still think the Suns showed as much defensive effort as I've seen from them in the D'Antoni era in last night's game and I think that's certainly a step in the right direction for them.
We'll see if it can make the difference in the spring.