I think that they are. They had a lot of talent already, but Mike Nolan just isn't that good a HC. I think that he can't "speak to the soul, in order to electrify" his team. He's a great guy when calling plays from upstairs. Much like Dom Capers, I think.
Singletary, on the other hand, appears to be made for the sideline. I think that he will make some questionable decision, but he'll get that team ready to fight and flying all over the field. Just look at Parys Haralson for instance. A guy with tons of potential, which really (arguably) didn't come out, but now he's flying over the field, making plays. (Was hoping we'd snatch him away from the 9ers this off-season).
I think that the 49ers could turn some heads against the Vikes. Mainly because Shaun Hill is horribly underrated, Vernon Davis who seems to finally be having his coming out party and Frank Gore who can run it. And of course, that defense could keep them hanging in the game. It's a long shot and I would still put my money on the Vikes, but you never know.