As for the 2nd film, I thought it was a lot of fun as well but I still feel that Sly hasn't managed to quite nail the tone that he has been going after and seems to be even more aware of that than ever for the 3rd film.
I think the tone he's going for is simple. Old fashioned 80s action flick. I was tempted to say "with a slight touch of tongue in cheek-ness" but then I realized that's practically redundant.
I think the problem is that nobody seems to know how
to make those movies anymore. The look to them is far too stylized, gritty, and goes for an overly-realistic Hollywood touch.
Maybe if they cut down on the visual effects like how they seem to give everything a certain tint with computers (especially obvious in night shots) and simply went with he old fashioned "actually filmed in daylight with more or less natural lights" it would feel more authentic.