Recently closed tabs is a feature well used. It used to be unlimited number of entries, but only got 10 entries now.
Why to have more recently closed tabs entries!
There are times and situations that 10 are not enough, especially while someone is working or researching or both.
There is the need to go forth and back to a lot of tabs to grab pieces of information.
There was tab stacking some time ago, that gave you the ability to manage your open tabs to groups, free tab bar space, and easily find your way through a large number of open tabs.
There is also the issue that too many tabs crash opera, or make things "heavier" and slower, so its essential to close some tabs to free up resources and space in tab bar, and then easily and quickly reopen them through Recently Closed tabs.
In overall: More recently closed tabs add to more efficiency!
Opera used to be the fastest browser, not only in terms of loading speed, but mostly because it allowed you to do stuff with less clicks and less mouse hovering around the screen.
Please consider bringing the feature back to its more "helpful" state!!!