I have used several years Chrome, Firefox and before to switch Opera, nearly three years used Yandex Browser. It's based on Chromium, Opera Turbo tech etc. also.
After that transition to Opera I have seen to many missing feature in Opera unfortunately. And prepared a quick list when see any cons of Opera. After of use I will add other missing features in that list. Other users can send their views on this topic that I will add them into list also.
Opera Browser's missing points:
This is not the suggestions forum. This is the technical support forum.
Most of those features have been requested already.
Where to suggest really do not know coz Opera's forums are very weak as I see until now, sorry if open the topic wrong place.
If requested then no problem but I will add if notice any missing feature. Thanks