Without some adjustments to the vote, the vote buyer is going to lose out the most?
So this could mean less bids in general, or the vote being shared between fewer posts making it tougher to earn curation on front running as less bids=more competitive in the ideal vote timing?
With 50/50 split yes, the voting services will have to give higher upvotes because only 50% returns to vote buyers
This means less upvotes from bid bots but with 50% it will also give more curation rewards - so it should balance itself. But really no one knows what's gonna happen :)
Bidbots can return 90% of the profit form the bids and curations (similar % to current model ). However, there are some risk associated in calculating the curation and get hit by downvotes. In this scenario, bidbot can share curation profit when curation is matured (i.e. downvoted post will lose curation). The probable positive outcome can be that thrash trended by bidbots can be hit by the downvotes. The bidbot users will lose the the Steem/SBD spent and curation, be careful about using bidbots next time and leave the system. However, it will mostly depends on the downvotes to discourage the shit content creators to back down (to be seen).
However, there are other alternatives for delegation for tokens such as @steemhunt, (or, @minnowsuppot, @leovoter) provides 20% ROI in terms of HUNT, Steem and SBD.