YES. I would think you'd need a decent explanation, but honestly, it doesn't really matter. Sure, if you are an engineer, where the standard seems to be 5 years, than it won't be much cause for alarm. But these days, many students are taking 5 years, even for social science degrees and such.
I would pick up a double major or at least a minor, if not to cover your ass than just to have that on your resume later or whatever.
I would definitely find a way to stay another year, if that means raising your gpa. When it comes time for auto admit/ dings, law schools are too busy and frankly don't give a *&^% enough to see if your 3.5 was a product of 4 or 5 years.