Well, you gave 4 reasons to back up your idea. None of which is massively convincing to me, because:
1) new players more than anyone else are in need of c-bills. Paying c-bills for loaned 'mech would slow them down in buying their own things. And no, they wouldn't get an easy way to find out what they like to pilot and what they don't, - because this changes very quickly and dramatically as new players mature. Like, they could take a nice and mightily developed Atlas this week, pay for loaning it, and find they like it very much; then buy the same model to own it, using c-bills they piled up from their cadet bonus. But next week, they loan a jager, and suddenly realize that Atlases are piles of utter {Scrap}. After saying some not so nice words aloud, they enter a long grind in their own atlas to earn c-bills to get a jager. Exhausted from it, they sell their Atlas as soon as it'd be enough total c-bills to get a jager. Only to find out their brand new jager is nothing like the one they were loaned a ~week ago - it's clumsy, they don't have the weapons they want (more c-bills grind needed), modules for it a miles away in the future, - and overall, their old Atlas was a bit better for them. Which they just sold.
What would you think they'll think about loaning 'mech feature?
2) Any seriously competitive teams would NEVER allow anyone to pilot any mech the pilot is not closely familiar with. If he doesn't have it, - then he's not competitive with it. Period. Loaning would not help; i mean, any reasonable person wouldn't loan a mech for at least many dozens battles he needs to get familiar with, - and then keep loaning it to drop with the unit, - because it's so much reasonable to just buy the thing and own it.
3) Some of paying players would have incentive to purchase more if loaning 'mech would indeed be popular thing. I.e., if there would be "clients", so to say. "Some" - not all, - because many of paying players would not bother to do it; others would see it as an activity which potentially creates unnesessary tension and negative emotions - by not all, but some of "clients". I am a paying player, and i am both of that. Even being relatively new (playing for a ~month so far), i already have 2 mastered 'mech i don't play at the moment, - but i'd never loan 'em out to anybody except for a good friend and for free (no payment from him to me). Those "paying customers" who'd lease my mech for their c-bills would possibly leave a mess in the cockpit, too!

Next, for the loaning to be popular - i.e. for many players be willing to loan a mech, - well, there must be many players willing to loan a mech. Which, considering the above and the following, is doubtful to me. And, if there are few to none players who would be willing to loan a mech, - then, correspondedly, the incentive you are talking about would vanish. How PGI can be sure it'd work, then? I guess PGI can't be. And, i guess, PGI wouldn't be willing to implement a feature "just to see if it works". You know?
4) Old players might search for new players even now, - if they'd like to do so. Extra c-bills as an additional incentive? What kind of friendship it'd be, if the old player's significant reason to get in touch in the 1st place, - is desire for c-bills? Besides, many, if not most, of old players have mountains of c-bills already. More than they need. And often, same with friends: being an old player is likely to mean you have lots and lots of friends, familiar with lots of people who are not your friends, and are overall buried under more social interactions than you would possibly want.
I am not saying your idea is {Scrap}; but i am saying some alterations are probably needed before it might actually be more useful than useless. Myself, curiously enough, i'd imagine that loaning 'mech to someone for a _negative_ price, - i.e., giving them a mech to pilot, AND a sum of c-bills on top of it, - may be a thing i'd like to be able to do. Simply a gift of some c-bills and a mech or few for, say, a full month to control, given to my new friend in the game? Sure, i'd like to be able to do so. Possibly many other players, - among whom some are indeed very "old" players, - would possibly like to be able to do that, too. But earning c-bills outta new players? Geez. No, i wouldn't like. We have enough difficulty with many casual players turning away from MWO simply because it has not exactly standard FPS-like controls. No need to make more potentially-upsetting-for-some-of-new-players features, really. I mean, gotta be very careful with it, you know?
Cheers!
Edited by FinsT, 22 October 2013 - 04:58 AM.