I do a lot of Wordpress development as well and I'm not a huge fan. This GitHub repo has a long list of flat file CMS options:https://github.com/ahadb/flat-file-cms
I've used Kirby and found it to be pretty intuitive if you have a custom design. The thing that is lacking from these other options is a lot of theme options which Wordpress has a plethora of. Often my clients don't have the budget for a full fledged design and there are plenty of Wordpress themes out there which make it easy to have a decent looking website (mobile responsive, custom fonts, intuitive layout, etc). Hope that helps.
I've used Kirby and found it to be pretty intuitive if you have a custom design. The thing that is lacking from these other options is a lot of theme options which Wordpress has a plethora of. Often my clients don't have the budget for a full fledged design and there are plenty of Wordpress themes out there which make it easy to have a decent looking website (mobile responsive, custom fonts, intuitive layout, etc). Hope that helps.