I think this is the wrong thread for that but I'll throw in my $0.02 anyway.
The actor portraying Frank is not the most important aspect of the film. If you look at Warzone, Stevenson was a pretty decent Frank and the movie still sucked so incredibly bad. What a GOOD Punisher film needs is the right tone.
In order for the Punisher to be decent, they need to capture the feel of Ennis' MAX books. I'm not talking about the gore or that dumbass black humor they had in Warzone. It needs to be a film that takes itself very seriously, is extremely dark and violent, but not cheesy, over-the-top, or gory. It needs a smart script that knows what the movie is about in the end: action. But serious , brutal action ala Taken, Man on Fire, etc. This film is all about tone. Something the Dark Knight did really, really well.
As for the movie's plot, I think Ennis' first MAX run would work extremely well for the big screen. Lengthy shoot-outs, a brutal and long fist-fight, a mature and surprisingly deep story. It has it all. Now add a few more scenes of action at the beginning to set the mood, get the backstory out of the way in 5 minutes or less (expository dialogue would work fine) and choose decent enough actors and you have your first true-to-the-character Punisher movie.
As for the actor, Stallone would have the celebrity pull but he might not be serious enough for this role. Maybe Gerard Butler or even Stevenson again could pull it off. It may be best to go for an unknown to keep down costs and potentially get a better actor.