Fortunately, the process of researching keywords for your domain name is the same as finding effective keywords for other uses. You can use tools like Google Keyword Planner and KWFinder to search for terms that have both a high search volume and (ideally) low competition. Just remember that in this case, you’re looking for a keyword that represents your website and content as a whole.
The primary reason I’m looking for an alternative to WordPress is its reliance on PHP. A language so awful I wouldn’t let it anywhere near my computer if I didn’t rely on WordPress for my blogging. Using PHP as the substrate for your CMS/blogging platform guarantees you’ll have day one security problems. Just look at all of the WordPress plugins and themes that have horrible security flaws (e.g., revslider).