Derek Ortt wrote:it would create a lower albedo, but only in the polar regions. So the waters would be warmer there
No argument with this part.
It may increase the negative phases of the thermohaline circulation, since that involves bringing up of the cooler waters. With more cold melted ice, that would provide more in the way of cooler waters.
The overall effect would be small, maybe 1 storm less per year
Ummmm ... if the thermohaline circulation were weakened, this would indicate a net reduction in tropical upwelling and in surface transport of heat poleward. That's the opposite of what you are hypothesizing.
BTW, I'm not convinced there would be a major weakening of the THC (even in a strong warming scenario) - some model work I've seen implies that the rate would remain similar but with the subduction area displaced somewhat.