Slowness of the UI
WordPress stands out as horribly slow, when compared to other PHP solutions that I am familiar with. Any particular reason for this? They run on the same host and against the same MySQL database, so I am comparing apples to apples. This is pointed out to me by my hosting users for whom I run other PHP and MySQL-based solutions that respond practically instantaneously, whereas WordPress takes a long while to load a page, and then this page reloads several times, shifting around controls when it looks like it already loaded.
They are on 5.6 and php 7.0. We benchmarked MySQL and Php and found no performance issues whatsoever, so the slowness is within WordPress. The solution currently has 1 main page, 1 contact us form, and 45 products in 12 categories under WooCommerce. The database backup size is 600 kB. Our "fast" solutions have gigabytes of data and hundreds of pages.