I agree that's a fair compromise. We already have comments and 2-10 set as a separate dial in our configurations, so it's easy to tune them to 0 while only tuning the main account to 50%.
Using upvotes as VP overflow was part of the reason we offered rewards on all posts/comments. The potential for abuse was always there, but the incidence rate was very low until HF21.
Good to know it wouldn't be difficult from a back end perspective. I haven't heard many say it would be unfair and it wouldn't be too difficult to change if people did have a problen with it.
I don't think anyone had a serious problem with vote trading before hf21, except for a few people who still have other priorities at the moment. Also, there were much better ways of abusive rewards back then, and SBI has always been of limited size compared to whales, so SBI abuse wouldn't have made sense for the large and visible accounts.