I'm going to be selfish here and ask what WP can do even though I'm not using it yet. I'm using NucleusCMS.
In my current NucleusCMS site, I have 2 blogs in one installation.
site.com/ < this is the URL for first blog, you can see posts from BOTH blogs here, arranged by post date.
site.com/blog2/ < this is the URL for second blog, you can only see posts from blog2 here, plus they use a slightly different template with voting plugins.
There's also search and tags and they work across both blogs (returning results from both). RSS feed returns posts from both blogs as well.
So the question is, can this be done with WordPress?
The problem I'm having with said NucleusCMS site is that it doesn't have "pretty" URLs by default, and when I install an URL which lets you have custom URL for each post, it eats up ~140 MySQL queries for each page. That's the problem I'm trying to solve by moving to WordPress, since it has so much more users, support, plugins, etc. and also SEO URLs as a default feature!