when the total conversions of regular accounts more than double the stabilizer's conversions

Where have you seen that? From dalz's chart, which is only for accounts with conversions above 1000 dollars, that's true. But I don't see how including the smaller ones could tip the scale so dramatically.

If we want users to convert their Hive to HBD, shouldn't we increase the HBD APR?

I heard it's been considered, but to be honest, it's not like that. There are four categories of people using the HBD to HIVE conversions, other than the stabilizer:

• people or projects who receive HBD regularly (from the DHF, usually) and want to optimize the amount of HIVE they receive at this time of the market (for Hive, it would be preferable if they used the internal market, but it's their decision)
• speculators
• big HBD holders who might have an issue with the APR dropping and want out (I haven't seen any of those in dalz's chart that I could recognize as doing it for this reason)
• small users who don't know what they are doing anyway and confuse swapping with converting

If the logic for increasing the HBD interest would be to convince people to keep HBD in savings rather than convert it to HIVE, I believe it won't work at this point. The incentive is higher to do the reverse and wait on the volatile coin, rather than stay on the stable one, at any (reasonable) interest. The problem is how is being done, in my opinion. This is not a time for personal optimizations at the detriment of the blockchain.