I don't think it will really be a problem. You still need the horn and the brain and only 1 in 3 organ runs will be one where the portal for eye opens last, so you can save one keyset.
Organs get offered here very rarely and if for some reason people start offering lots of eyes, they will simply land on the DNT list. There was no organ market here so far, so nobody will be at a disadvantage when there won't be one in the future.
Of course, you will need a few less keysets to get a torch, but the number isn't that great. IMO it's a waste of time to buy eyes to save one keysets out of 9 when retrieving organs.