Yes - you nailed it here. People get scared when they hear '50/50' because they feel like they'll lose rewards on their posts. Instead, it will be more worthwhile for people to start upvoting (ha, or even buy STEEM to so they can 'earn from reading' - not everyone is a content maker!). As a nice bonus our trending page would be filled with content instead of just being an overview of people who post 'a just nice enough piece of text so I can legitimize my vote buying'.
As always, people are creative and we're unable to predict how a new system will be ab/used, but in principle I'd be pro a 50/50 split.