Unless you and I are using completely different definitions there are a fair number of bruisers, all of whom are doing very well at the moment, that auto attack quite a lot. Jax, Jarvan, Xin, Olaf to name a few bruisers who spend a lot of time auto attacking. If BotRK would work well for Melee Carries why wouldn't it work well for these bruisers that are already in a great position?
Of particular note is Jax, one of the most historically problematic champions on dominon, currently bordering on OP. Riot Nome has specifically stated that he's hesitant to bring items over from TT that could make Bruisers/Jax stronger. That, more than anything else, is probably why it's not in at the moment.