User blog comment:MisterWoodhouse/Social Activity, the 2010 Editor, and Unpausing Migrations/@comment-172.56.22.248-20201121214625

Here are all of the flaws me and other users have noticed about UCP

The Editor:
 * Bounces up and down whenever you type.
 * The header is a mess.
 * It is slow to update.

Comments/Message Walls:
 * Cannot be edited after a day.
 * Comments no longer exist as separate pages.
 * Message Wall Thread URLs are different and old links do not redirect to the new ones.

Photos (I learned these from a blog post):
 * The same photo cannot be used twice.
 * Photos are now 100 times larger.

Other/Miscellaneous:
 * User profiles now only show bio.
 * Lag.
 * Multiple functions take multiple steps to perform.