Denise has played a rock solid game. But yeah, doing what needs to be done at the end could make a great argument for her as Sole Survivor. This post is based on the assumptions that Abi gets voted out this episode and Malcolm finishes fourth.
Outwit, Outplay, Outlast.
Hands down, Denise has the best argument for Outlast, since she went to every tribal council and was not voted out.
If she can get Malcolm out, then she'd be the best example of Outwit and Outplay. Lisa and Skupin would have a hard time convincing anyone that they earned those accolades.
The 4 people on the jury from Tandang have plenty of reasons to vote against Lisa and Skupin. They went into the merge with the tribe intact, yet the first three boots post-merge were Tandang. Abi is the wild card (duh).
The three Kalabaw have every reason to vote for Denise. She helped all three of them make the merge by allying with them, and those three are more likely to vote for someone who's played well. They'd definitely think Denise played better than Skupin and Lisa, and be able to get a dig in that Tandang made the merge intact but didn't win.
At this point, the only final three that would be interesting is one that includes both Denise and Malcolm. I think Malcolm would win, but at least Denise would be some competition. If Skupin and Lisa both make the final 3, then the third person wins in a landslide.