This doesn't mean you should look for a trouble and not prevent potential problems with better coordination / planning and carefully weighting the pros / cons of a particular decision. Merge conflicts and huge refactorings can sometimes have nasty consequences in a form of huge release delays, bugs and inconstancies surviving for months and even years after the "stable" release.

Would you be happy if someone asked you to merge 3 long lived branches, the first one being a complete UI redesign, the second one complete UI translation and the third one - complete refactoring? Maybe I am exaggerating but sometimes I have experienced things that were not very far from that.