For Titanfall, I think you could put in two different kinds of leveling. You'd have basic Xp, gained by defeating enemies with the occasional big bump for finishing a mission, that covers stuff like basic attack bonuses and upgrades for the mechs. However, you could have a second system of Burn Cards that players earn individually for stuff like going above and beyond (not only did they find the secret training camp, they abducted the top teachers and burned the place to the ground) that give them special bonuses, representing favours from commanders and fellow soldiers; heck, if you get enough Burn Cards you can cash them in for some help with your career, getting a permanent new rank (from Captain to Major, maybe) with accompanying bonuses to your command score, the number of Grunts you command, how many Titans you have available for your campaign, etc. It gives a decent connective tissue that provides the characters with advancement without having to either nerf them at the beginning or have them super-ridiculous in the endgame.
In Destiny, I think you're missing a great source of RP: Your fellow Guardians. I've run a game similar to that (fantasy, a fortified place at the edge of the Wastes where a great empire used to stand before it was overrun by monsters that was the base for raids to recover artifacts) and while the players didn't care particularly for the political factions, they loved dealing with the other adventurers who went out into the dangerous lands and raided dungeons beside them. From occasional allies, friendly competition to bitter rivals, that personal touch is where the RP comes in. Don't tell me you've never forged a bond with someone while completing a raid with them, or gotten pissed at the person who jumped into the Murder Cave too soon and ruined the spawning. Keep on the Borderlands is boring if all the people there are faceless mooks; add some names to other Guardian teams and it'll be fine.[footnote]On a related note, does anyone know a system that does nanotech well? I've been turning over ideas based in Destiny for a while now, but I need something to dig into to help we work on the tech angle[/footnote]
Finally, for Shadow of Mordor, I think it was Jon who said at the end that there would be a lot of work building the ally system? You could take a page from Apocalypse World, and use the advanced Manipulate results for the different types of partnerships:
> friend (impulse: to back you up)
> lover (impulse: to give you shelter & comfort)
> right hand (impulse: to follow through on your intentions)
> representative (impulse: to pursue your interests in your absence)
> guardian (impulse: to intercept danger)
> confidante (impulse: to give you advice, perspective, or absolution.)
In fact, a lot of the Fronts and Threats system could be retooled to make the Nemesis system viable in a tabletop, and give different but equally evil motivations to the Uruks.