Do we really need more Metal Gear?

I love Metal Gear, it's up there with some of my favourite franchises ever.  I started with the Metal Gear Solid demo on my playstation, ended up buying the full thing and being hooked ever since and as much as some people like to rag on it's outlandish, insane plot which could arguably use some editing, I still love that stuff.

So on the horizon we have Metal Gear Rising: Revengeance and Metal Gear Solid: Ground Zeroes, but do we really need these games at all?  Now I don't want anyone to take this the wrong way, these games do not look bad by any stretch, in fact they look awesome, but they worry me. 

The story for Metal Gear was done, finito, over with MGS4 and while I'm not going to turn my nose up at more Metal Gear goodness, I'm worried that one day, if they keep making these games, that they are going to end up sucking.

We have seen it happen to Silent Hill and Sonic just to name a couple of franchises that aren't anywhere near as good as they used to be and I really don't want to see Metal Gear get the same treatment.

I'm pretty hyped for these games, and they'll probably be good, but please....let it die and be remembered as a great series before you ruin it with spin off crap.