Right, I know it will work if you don;t edit the display name. But one often will want to do that. If you were writing a column, say, you might say "In Dick Francis's novel Refusal, the author soes thus and such." That link is clickable. It would work natively in Pages 5, as in Pages 4.3, in a TextEdit document natively or exported to PDF, and in Apple mail, etc. It also works when you export from Pages 4.3 to PDF. In Pages 5, however, it only works (after the first page: who knows why it works on the first page!) if the display name is the same as the html code. This is a bug, or sloppy programming, or both.
I like Page 4.3 quite a lot. I has its limitations but it is simple without being simplistic. I had high hopes for Pages 5. Now that we have 5.1, though, I see that it is just not going to work for me or for my businesses. There are little things like the inability to set the default zoom (which is acutally quite annoying if your eyes are not so hot), the inabilty to see|print comments and big things like the lack of Applescript support, bookmarks, and mail merge. I thought Apple was going to be bringing back these features, but I see now that they are committed to the lowest common denominator. The people who say Apple is is the business of making "toys" are, alas, correct. I guess the business market is not big enough for them. I've actually removed pages 5.1 from all our our macs, and have removed 2.1 from our ios devices. We still have a few stray documents that were created or edited with Pages 5, but I've discovered that you can use Pages for icloud to download a pages file in Word format. Pages 4.3 can open and edit Word files, so that is a (cumbersome) workaround. We'll continue to use 4.3 (and 1.7.2 on the ipad) for the time being, but obviously will need to find something that has current support going forward.