They should have just named it "<New Browser Name>" by Opera. It would set the expectations right. When its the same name and a higher version number with most of the features missing it just alienates the existing users.
This would give time to add new features to the new browser while keeping the existing users happy with what they already have. The existing users would not crib about missing that one obscure feature that no one else uses.
In the current scenario the power users who normally jump to the next version end up missing the features they are used to. The best example in this case would be Phoenix/Firefox which rose from the ashes of Mozilla Suite. The stripped out all the fat and made a lean browser. What happened to Firefox after version 4 is another story.
This would give time to add new features to the new browser while keeping the existing users happy with what they already have. The existing users would not crib about missing that one obscure feature that no one else uses.
In the current scenario the power users who normally jump to the next version end up missing the features they are used to. The best example in this case would be Phoenix/Firefox which rose from the ashes of Mozilla Suite. The stripped out all the fat and made a lean browser. What happened to Firefox after version 4 is another story.