I fear the voting time limit, will create an environment where people are just scrambling to vote on posts that are between 10 and 45 minutes old, with everything else being largely ignored. This would kill of a lot of people's enthusiasm for Steem. Especially the ones like me who are asleep at the most active Steem times.

I'm highly skeptical that this is going to be a real problem. My guess is that most people are not interested in voting reward harvesting. There are some, but the question is: should we care?

The most important thing from the perspective of whole system is that are people going to vote enough? If most people are voting primarily because they like the content, as they do in every other social media platform, then the new rules are not going to be a problem.