I think it mainly comes down to how his athleticism transfers to FW. The main reason he used the strategies that he used in many fights people thought were boring were that he was fighting guys that were way bigger than him. You look at Pettis, Bendo, Maynard, and even guys like Danzig and Nate (the Nate fight was pretty good, by the way), and then you look at Guida, then it's clear that what he's naturally good at isn't gonna be enough to get over the size difference. But, if you look at fighters that were either closer to him in size or who were at a lower level than him (it should be noted that, even though Guida's had to use strange strategies to beat larger opponents, he's still given them extremely tough, close fights and even beaten some of them), then he fights in a different manner.
Look at the Tyson Griffin fight, for example. He was fighting a guy that was way closer to him in size than anyone else, and he didn't rely on the crumping striking style, the wrestling-heavy gameplan, or the shoulder strikes of doom. He knew that, because one mistake against this guy didn't mean he'd get overpowered and reversed and either KO'd or subbed, he could take more chances and fight in a much more natural way, and it led to a FOTY candidate and a fight that many people feel he got robbed in (thus assisting greatly in many of the counter-cases for the, "Guida's only exciting when he's losing!" arguments).
There's also a lot of examples of fighters getting faster or stronger (or both) when they drop down a weight class because their physique changes to better assist in the weight cut, and I think we might see this when Clay drops down to FW, which is a very important factor to consider.
So, anything could happen in this fight, but I think the deciding factors will be two things: