I don't really think you can untangle the two things. Yes, you currently see larger stake holders voting on content over at smoke.io, much moreso than here on Steem. But if there was the opportunity for greater ROI through delegation to bid bots on smoke, would we still see the large stakeholders voting? Maybe, maybe not.

I honestly don't expect it would change much here on Steem to go 50/50 split. Even with 50% curation, curating other authors content is still not the optimal play as far as maximizing ROI when compared with self voting or delegating to bidbots. We already know that the majority of large stakeholders will act to maximize their own ROI, so 50/50 curation wouldn't change much. It would just make it so that the stakeholders who act altruistically for the good of the blockchain at the cost of their own short term ROI are not sacrificing quite as much by voting other people's content.