This is alomost as bad as GL saying Jango Fett wasn't a Mandolorian.
But yeah. Lucas has two characters on screen that are connected with the Mandalorians, but aren't actually Mandalorian? What a useless device that is.
This is kind of a big failing of his, actually. He's claimed to be a merchandising genius, but he creates two characters that are visually very interesting and then he goes and kills them off in a movie or two's time.
I suppose that you could argue that it only adds to their mystique (which it obviously does) but then he lacks the conviction to stick with his original intent (which I guess is not very surprising) and then brings them back later on. Even though he's had nothing to do with Boba aside from saying he wouldn't have killed him had he known how popular he'd become. Not that that stopped the EU from going very long after ROTJ before they brought him back.
Granted, I believe Katie did most of the writing/conceptualization behind the Savage Oppress/Asajj Ventress storyline and thus probably shoulders the blame for Maul's return...
Nevertheless, I'm very interested to see how it plays out, but I am sure that those episodes will enter into my canon in the "Infinities" section. =P
I'm kind of shocked that Frink doesn't know of Boba Fett's survival, I gotta say.