This will depend on what your goal is.
If you're looking to throw your hawk, I'd leave the edge as is. Changing the bevel of an axe edge to a knife-like angle will promote slicing, not chopping... and with a throw, you want to split through the target. If the edge is too sharp, it will tend to bounce off your target, and you'll be forever resharpening it.
If you're looking for a hand-to-hand fighter, you can certainly put quite an edge on it. However, the hawk is designed to be used like an axe, and not a knife--in other words, it'll do more damage chopping and driving into bone than it will ever do by slicing and cutting like a knife, simply because of the way it's shaped.
So if you're looking for something that will cut and slice pretty well, you can take out a few more degrees of bevel, especially if your hawk is already fairly 'dull.' However, don't go too far in sharpening it (in my opinion)... you'll have diminishing rewards (more work than it's worth).
If it's already sharp enough to slice paper, I'd say leave it.