Hello BGL,
That was a change based on usage of lending over on Bitfinex. We think it's a good compromise, between being small enough to not push out small lenders, while avoiding lot of small offers that may interests you but doesn't bring much in term of liquidity. The idea was not to lower interest rates (which I don't think it will do).
There is a trick for very small lenders: if you use auto-lending, the minimum amount is 10 USD for an offer to be posted.
This amount of $100 won't be increased in the future. We still want to address people who don't always have a lot of savings and offer them a way to have a good return on their investment. This won't change.
Thank you for your comprehension

Raphael
Bitfinex