Reddit was grown to be the top 23 most visited website without any monetary incentives, so I think the evidences shows the comment reward pool isn't necessary to attract people to Steem.

Also in the early days of Steem people could make a simple introduction post and make in the hundreds and even thousands of dollars rewards but a lot of people just wouldn't join Steem and make the no-brainer move of making those posts. (I can name many of my friends and I heard of many more)

There is no need for separate reward pool to attract people on Steem. Are there good reasons for separate pool? Maybe.

Trending comment would need a section on themselves or how are we suppose to find those great comments and conversations.

I don't know the best way to go. It's a tough call either way.