Main Characters - When is Enough Enough?

Something that I think a lot of us don't really think about when it comes to games and gaming stories in general is the focal point of it all in the main character.  They are our input into the game world and they allow us to do what we want (and sometimes force us to do exactly what we don't want) so it's easy to think of them less as a character and more as a tool for accessing this world.  Some games allow this feeling moreso than others, but regardless of whether you're playing Uncharted 2 and having Drake jump off a cliff for your own amusement, or having Point-Man in slide across an office just because, it's likely that in every game, you're going to do something that the main character isn't going to do.  There's always that disconnect, even when you feel more or less attached to an MC, and even though the story generally centers on them, we don't always feel that way because, well, it's a game, we're supposed to do what we like.

But the strange thing about that is that we're so particular about our Main Characters after we've played them and grown accustomed to them.  To the point where even subtle changes to a character's design, or even big ones, like Cole from inFamous 2 big will inevitably drive some people insane no matter what.  And no matter what you do, people will notice.  If tomorrow Mirror's Edge 2 was announced and there was a design on Faith's gloves, someone will find a reason to go into a tirade about how that's a bad thing.  I guess we leave a little bit of ourselves in them in the memories we've gathered while playing as them, so even though we might not really consider their main story or their overarching goals or anything of the sort, the minute we learn that they won't be there anymore it really strikes a chord.

Honestly, this line of thinking was brought up with the recent announcements of Mass Effect 3 being Shepard's last outing, while Halo 4 is a sort of 'new beginning' for Master Chief.  As a random side-note, the quote of "343 wants to sell "the fantasy that Master Chief is an 800-pound hero that is part tank, part jet fighter" with the Reclaimer Trilogy."" is quite possibly one of the dumbest things I've read all week.  But anyways, it got me thinking about main characters in video games in general, and it brought me to the question of "When is enough enough?"  Is there honestly a tangible amount of screentime one main character can get before he or she is truly not needed anymore?

It's a hard line to walk, honestly, as some would argue that certain games just wouldn't be what they are without their main characters (Uncharted series, inFamous) while the same was said for other series but then the general consensus was that it is in fact possible to be a good game and a good addition to a series without the same MC (Metal Gear Solid, for example.  No, not Raiden, Big Boss) so long as the game remains functionally similar.  Some series of games seem to only get better with a new Main Character (Going from Altair to Ezio in Assassin's Creed, though that could be argued on several levels, I'm sure) at the helm.  And then there's series where the change in character....well, didn't really seem to make a difference at all.  (F.E.A.R. series is what comes to mind first, but really, a lot of games that aren't known for their narrative could go here)

So what's the difference between this series and that when it comes to how the Main Character can or cannot be switched out?  Is it only okay when the narrative provides compelling reasons and a satisfying end to the character?  That would likely be the most agreed-upon answer we're likely to get out of the question, in all honesty, since it's an opinion and thus not something that can really be gauged as true or false.  But it is an interesting point to question, regardless, since for all we know, the next game in our favorite series could be the next one to roll out a completely new main character to spark the whole debate again and again.  I know if inFamous 3 starred someone besides Cole MacGrath, I would have some grumblings about it.

And for my own interests in this, I will say that there are some games for me, personally where the idea of a new character is quite possibly the worst way to go (I could have made a better Drakengard 2 in an afternoon), whereas on the other hand, some games have gotten it just right, (Zone of the Enders:  The 2nd Runner springs to mind, eventually) but I don't subscribe to any particular theory of which is 'right', when it comes to keeping a character or making a new one for a sequel as it's mostly a case-by-case basis.  And this is not to make mention of the Legacy of Kain series, of course, which has gotten it the most right of any series in my opinion.  But that's a point I plan to elaborate on at another time.