Yes, a year is a long time in website development which is why it astounds me that you have not got the bookmark system sorted out yet as it was in Opera 12. It surely can not be that big a deal and as it does seem to be a major sticking point in people transferring over from Opera 12 to Opera 25 or simply going to a totally different web-browser it seems somewhat short-sighted.
What is the reason why the bookmark set-up has not been put into Opera 25 properly? There must be some reason.
Although it might be too late for me: my Opera 12.17 has just started crashing every 20minutes even having this website causing the crash.