Future entries in the Metal Gear series won't be about stealth or action specifically, rather achieving your goals in the way you see fit. That's what Hideo Kojima said when asked by CVG about the increasingly more action-based nature of the series. It's a fair answer and one that reflects a more open, western approach to a title.
"I don't want to feel owned by labels," Kojima explained. "It's not whether it's going to be stealth or whether it's going to be action. What I want to accomplish is to give players the ability to play the way they want to play. If they were actually put in that situation, I want to give them the freedom to do what they want to."
Metal Gear Solid 4 almost had it right, the ability to sneak whenever you wanted to or run and gun if that was easier. The problem was, there was no real cause and effect. If you were clever, running and gunning was easier and quicker than stealth and had no real punishment. Many players, even long-time series fans, just decided against stealth altogether. With a little more polishing, it'd be interesting to see what Kojima and his team could make of the "do what they want" method of play – very interesting.