Yeah - I just read this too.
I'm a little disappointed by that - I was hoping they'd have the confidence not to have to re-visit Arendelle. We've never had a true Disney Classic sequel before (apart from Rescuers Down Under, and look how good that was...I'm not even going to mention the DVD sequels) - and this decision really opens up prospect of more animated sequels (like Dreamworks...and we've already seen how Pixar now thinks sequels are important - Cars, Monsters Inc, Finding Nemo, Incredibles). Disney was the one hold out of animated cinema sequels - allowing their classic fairytales to stand alone.
I'd have preferred them to continue making their live action sequels/remakes, rather than producing CGI sequels...but that's just me (of course, I'll still be lining up for them!!!
)