Although the 10% cap limit is pretty conservative and was arbitrarily selected in the past, removing it can end up very, very bad for Hive during the bear market (printing a massive amount of Hive because of HBD conversions). I believe there is a common agreement among witnesses to increase it during the next hardfork.
There is no point to compare HBD to any other DeFi coin as none of them are debt based (AFAIK).
I concur. I say leave the cap for now.
As it was arbitrary it would be interesting to change it and see what happens over a few ups and downs of the market. Everything is very new, so experimenting without fully compromising would be a way to test how things go over a long period of time.