Chronovore, what did you like about Mercs 1 over Mercs 2?
The missions in the original were much more challenging. If I didn't know better, I'd say EA's involvement dumbed down the missions to where anyone could finish most of them. The AI... now don't take me to be one of those chumps that says "the 360 version looks like PS2 graphics! PS1 even!"... but the AI in the first one seemed better, tougher, or maybe the spawn points, approach vectors, etc. were just more well-considered in the original.
I am not a fan of the Mercs 2 tattletale system they implemented for reporting faction transgressions. I played Mercs 1 like a stealthy little squirrel, and most of the time the factions didn't know where they were being hit from, much less who was doing it. In Mercs 2, I'll be at low health, and suddenly some guy on the other side of the battlefield calls in my transgression. And then another guy, 10 seconds later. And another. In short, it's basically impossible to manage my own rep through my actions, because the AI knows who is attacking it automatically.
Oh, also: BUGS. I've been reported in Friendly camps for doing nothing other than walking through them. The other day I was driving across a bridge, and I think a nuke went off nearby. Fiona bitched me out for civilian losses, and I lost a hunk of money. Only problem is, I hadn't called in an airstrike. :-]
The scope of things, and while you CAN ignore things, the ultimate goal is to get the best possible ending, which causes the game to be straightforward and loses its free-roam. Not to mention the game itself is timed, survivors to save, etc. That is not very sandbox, to me. In Saints Row, or GTA, you wind up at the very end regardless, and ignoring that gives zero penalty. If that makes sense.
EVEN THEN, when you beat GTA, Saints Row, etc, you are still given the option to fuck around. Dead Rising just gives you a NewGame+ and you're back to square one.
What you say makes sense, but I think Dead Rising has that too. Two endings? That's not much difference. (It's only two, right?)
It's splitting hairs, but SR1 pretty much shuts you down when you finish the game, but you're free to re-load anything prior to that mission and continue. If a sandbox game is determined by its beginning and endpoints or lack of them, Dead Rising qualifies; IIRC when you fail a story mission by anything other than player-character death, it gives you the choice to re-load from save, or continue playing outside the story.