It's really difficult for content editors to upload and find images - a pretty core CMS function.
Template creation is really clunky and requires a pretty experienced Crownpeak developer. A .NET dev can eventually pick it up but the lack of documentation and community resources severely limits on-boarding new devs.
There is no source control for code.
There is no support for minification, bundling, SCSS processing, or other modern dev tools
Only Visual Studio 2015 is supported for their Crownpeak Desktop Connection (CDC)
If you want live code to run on the server, you need to do some pretty hacky things - like writing C# that writes C# that can run live. Yuck.
Only allows for outdated .NET webforms (no MVC - though CP might say otherwise)
Publishing is often very slow or gets "stuck" - requiring CP support to unlock the queue Review collected by and hosted on G2.com.