I'm in Canada, bought my Twin in February, had them install the heated grips.
I'm coming from an 07 GSA with OEM BMW grips.
The Twin grips got just as hot as my BMW did, which is plenty hot.
I have no answer as to why mine work fine in comparison to many who have had issues. My guess is that the controller I have is from a new batch. That would explain why they work properly for me.
It's very Japanese to not admit fault, but to quietly just fix the problem. That would explain why there is no word from Honda that 'there's a fix'.