Apparently MSE questions are able to appear in the hot list, which the old MSO didn't managed to. Shouldn't MSE behave the same way as the old MSO in this aspect?
Well, at this moment, yeah we kinda do.
The plan was to have a system that let us push select, network-relevant discussions on MSE out to the entire network via the Community Bulletin Board. But, this isn't done yet. In the meantime, the hot list is a serendipitous way to keep the greater Stack Exchange community informed of what we're talking about here.
We originally thought having meta questions in the hot list would be a useful fill-in while waiting for this feature to be completed, but after further consideration have decided against it - so no meta questions will appear in the hot list.