Ever been to a tailor? That’s what custom software is all about. Put in features you want and take away things you do not want.
I’m a little biased (I run the company that makes Craft) but we absolutely love Yii here. It’s really robust and the codebase is remarkably modern, clean, and consistent, making it a pleasure to work with.
We picked Yii after comparing several frameworks including Cake, Symfony, and others (Laravel was just a twinkle in Taylor’s eye at the time), and it was a choice that we were happier and happier with as time went on and we got to know it better.
When Yii2 came out, so much had changed that we were basically going to have to rewrite the CMS anyway, so we did give Laravel a look then, because so many Craft developers also use Laravel. In the end we still liked Yii better for its speed and architecture. As we rewrote everything on Yii2, we came to love it even more - thanks to all of its improved flexibility and features we found ourselves deleting 100s of lines of no-longer-needed code. And deleted code is the best code.
Still not convinced? Read the Reddit Post