I'm testing BlueOcean in my environment and I ran headlong into an issue where when you try to create a new pipeline from a Bitbucket Server it only lists the first page of projects from the server to pick from.  Paging through the list would help but a filter would be nice as well.  Paging through the list of projects on our Bitbucket Server's interface is already slow due to the sheer number of projects so I'm assuming it would be a problem in BlueOcean.