When moving from Unity to GNOME, I have had a decent experience thanks to Ubuntu’s efforts at keeping GNOME “user friendly” (or at least users that don’t care for the GNOME team’s UI ideals). Decent, not great. The purpose of this post is NOT to chastise the team, but to commend. I appreciate what you have done with a DE that I didn’t think I would ever use. However, I noticed a few things that I felt were worth mentioning as concerns the experience.
First, while the default dock works well enough in most use cases, I very much miss Unity’s version. The reason is that I tend to use the dock heavily, and run many applications on my machine for both work and personal ends. Unity employed both smooth animation and a clever “stack” mechanism when the dock grew full. This both helped me to easily keep tabs on what was going on (and was visually pleasing) and made it’s use smooth and fast. The GNOME dock plugin in comparison feels very static, and when full must be scrolled to see it’s full contents.
The second is trivial in comparison, but some such as myself appreciated the “chameleon” effect in which the dock would adapt to the average color of the desktop wallpaper. This isn’t a requirement to my everlasting happiness though 
Thank you to all involved in Ubuntu’s DE. I appreciate all the work you do to improve and maintain the user experience for desktop users (I imagine the desktop icon situation alone is a handful enough). I have used Ubuntu for many years and am very grateful for such a product free of charge.