I think most people are afraid of the 50/50 because the first thing that comes to mind is that they will lose 25% rewards. 25% is a huge deal for people. The initial feeling is basically that the rich will "once again" take even a larger piece of the pie. Leaving the lesser accounts with more crumbs to compete for.
That being said, I am not as convinced as you are. I don't think that whales would curate more and that vote selling and/or delegations towards bid bots etc. would decrease. It might, but I don't think it would make such a big difference. People seem to be rather selfish and greedy in general, so I think most people would prefer 1.5x rather than 1x.
However, I still think this would be a good idea, even if I personally would lose some rewards. I think that some whales and orcas would curate instead of going the current route, and that would ultimately improve the overall experience on STEEM and newcomers would probably stay instead of leaving as quickly as they are today, as they would actually earn something rather than nothing. They would at least have a higher chance.
I think it would be a step in the right direction, even though I'm somewhat skeptical that it would make a huge difference for the majority of the large stakeholders. On the other hand, I don't know any whales or orcas in person, I don't talk with them and I've been ignored most of the times whenever I've tried to communicate with them.
Just do it. Who knows, it might be the exact change we need.
What people fail to realize is that in the future when sites built on top of Steem have ad share revenue with the authors, curators get none of that. Curators help authors get seen, and from there, authors can benefit significantly from being seen.