The problem with Bennett is not the wanting to roll the dice with him, I'd be up for it, but more of a financial aspect considering his next year's salary (which I'm assuming the option won't be picked up).
In all you really have until October or so of THIS year to evaluate him and make a decision on his option, and his option is an expensive one as it is.
If you don't pick the option and let him become a FA, then things will get tricky as well particularly if he does play well.
In the end you might be giving up some low cost assets for an unknown expensive one with questionable control over it.