Honestly, I don't think we need more banks - but @everittdmickey makes great points: savings and loans are not banks and neither are credit unions.
We are already a crowdfund, if you think about it. The more content we create, the more "interest" we earn, which increases the weight of our upvotes, which helps other content creators earn. Basically what might be missing from the banking aspect are whales who could loan STEEM or SBD with a contract & expectation of being paid back with interest - and a way to resolve conflict without nuking someone. Just some of my late night random thoughts on it. :)