That's a nice idea, and a nifty way of setting it up! I had seen these loan.create and so on methods, but never knew what they were intended for (and didn't investigate deeper yet ;-) ), but it sure looks like a good way of doing it indeed, and all on the native Hive chain.
Two initial questions popped up:

1. What are the requirements for an account to be the escrow? I suppose it needs to be a trustworthy account? And perhaps with enough juice to back things up?
2. What if the the one requesting (and receiving) the loan powers down everything is gone with the noorderzon?
   Now, to answer your questions:
3. Yes, I would invest in it. You gave the example of the benefits of microloans, and I've seen the same results happen indeed. So I'm a big fan of the system, it gives people opportunities, especially people in area (or circumstances) with little opportunities in general, I see it as a big plus! Also, Hive is quite popular in those areas as well, as a we discussed before, one nice upvote with rather limited meaning to us, can often be a world of difference for them. In comes microloans. On Hive.
4. I would if I see the need for it, at this moment, no usecase comes to my mind, but that can easily change of course. But, yes.
5. Good question... depending on the amounts, I would want to have some kind of reassurement that I will see my precious hive back in the future. Be it 50% backed by the escrow for instance, or base-amount to be recovered, without gains (interests), that would be ok I suppose. Also some kind of rating indeed, to prevent runners.
6. Needs is a big statement, but I certainly do see a great deal of people using it because it can bring drastic changes to their lives...

Now get back to the Hivefest thing you! ;-)