Well... that can happen if you think too much about mechanics, and too little about the character you actually WANT to play.
Now what I would suggest is - if you can muster the enthusiasm - to try fleshing out this one a little more. I gave you lots of options for backstory, but you mostly just went with my - very loose - suggestions. But that obviously means that the character is just a bunch of numbers, when in fact it SHOULD be so much more. OR you think deeper into what the character is thinking, right now. Go a little beyond what he says and does.
So, I think I' going to steal an idea from another game I'm playing in: I'm going to give XP for backstory - and at any time you write any. That shouldn't be a motivation in itself, but it might just add a bit of detail to characters who are otherwise too mechanically oriented. I can't yet say, exactly, how much XP you can get for a chapter of history, but - in order to keep the numbers relevant - I would base the amount on your current level, in some way. For example, if it's a fully fleshed out chapter, you might get one even encounter's worth, or something like that.
OR, if it's the mechanics you are bored with... well, it's in the nature of this game, that I or even you yourself can mess with a character more than normal. Is there another system you might be happier with when using the MARC? He could have some sort of breakdown, in game, and gain new abilitites, while losing the old ones.
One of the reasons I'd like you to stick with this one is that it's very flavourful, very cool, and I doubt you could play it in any other game. Also, I probably don't have the time to hash out another one like it. Any new character would have to be much, much simpler in design. And I fear if we spend so much time again hashing out mechanics, you'll have the same problems again with a new character.
So basically there are these two ways: Make the CHARACTER more engaging, or change the MECHANICS to give you more interesting options. Personally, this should be a character driven game. I know I'm not entirely satisfied with the way things are going - partly because this is a sandbox, and in a PbP that puts a lot of weight on the players to actually bring their characters into the foreground. Also, the strange party matchup is making things difficult. I'm inclined to let this change, basically, I would suggest that in the future only those people stick together who actually share some goals. And then I can try to create more story elements that mesh closer with their personal motivations. Right now we are very concerned with what is basically backdrop: the strange occurances in the desert, but that was in truth only intended to create conflicts which then evolve into world-changing events. And I wanted the character to be driving those events, too. So: You need more information. This is the goal of the current chapter. I'm hoping by the end of it, you'll have some. Then we can split the party into more homogeneous units and you can think about what motivates YOU to become active in that area.
Which brings me to my final point: We've been rushing even after event (no, I've been rushing those), in order to basically keep the game engaging. But that won't keep working. What we need is, that you guys actually talk to one another. You need to have in character conversations, to find out what kind of people you are running around with. You need to get a feel of the other characters around you. Without doing that a game like this simply won't work.
