Why get rid of Mouse Gestures?
For me, 'Open link in new tab' (or background tab) was the most used feature ever. Opera has had gestures for as long as I remember, and they were the feature that got me using it. Now most of them have gone, and the remainders aren't configurable. It's like they have been purposefully hobbled.
I disagree with operaid69, Opera has got some things right in these latter releases (right-click search opens new tab, links opened in new tabs are adjacent to the old tab). But it is way less usable than 12, for all the reasons that gave it this core following in the first place, and I'm finding it impossible to justify my continued support.