Well the larger problem here is what the sequels indicate: Disney is getting its way.
Bullshit. Disney already owned all the rights to all the Pixar characters as part of their distribution deals, and already had a Toy Story 3 in the works. When Pixar joined the Disney fold and John Lasseter became Chief Creative Officer reporting directly to Iger and Roy Disney, and Ed Catmull became President of Pixar Animation and Walt Disney Animation Studios, the first thing Lasseter and Catmull did was kill Toy Story 3 and put all in process productions on hold until they could be reviewed. All Disney productions were stopped until Lasseter and Catmull could review them and approve viable projects, with Meet the Robinsons being the only one that survived after they consulted with the director and the story was drastically changed to be much more personal and reflect director Stephen J Anderson's own story of being an adopted child. The biggest problem with Disney features was Michael "going back to the well for the 11th billion time" Eisner, and the screwed up structure they had Roy Disney relegated to since his direct report also reported to Eisner. Things got better after he was out of the picture.
Disney has been churning out utter dreck for years. Go ahead, what was the last good original animated Disney movie (not counting those made by Pixar)? I don't know, but I'm estimating something like 20 years ago.
Let's see... While these were not successful movies at the box office, they were good and suffered more from the decline of Disney Animation's reputation at the hands of Eisner than their own merits.
The Emperor's New Groove (2000)
Lilo and Stitch (2002)
Meet the Robinsons (2007 and has the John Lasseter seal of approval, and overall favorable ratings)
It's common knowledge that Disney had been pressuring Pixar to do sequels to all their hits because Disney can't think of or even appreciate new ideas. The big question a few years back was, "When Disney buys Pixar, will Pixar be able to maintain their independence, or will Disney's 'creative' minds start steering the ship?"
Pixar's creative team are steering the ship! The only people over them is Bob Iger and the board of directors where Steve Jobs holds a majority stake and Roy Disney is a huge Pixar fan. Why do you think Catmull and Lasseter both report directly to Bob Iger? Furthermore, Disney has never put stock in sequels. Sure, they've churned them out on direct-to-DVD releases, but until Toy Story 2, they never released a theatrical sequel. Pixar, however, is batting 1.000 with sequels, and NOTHING so far indicates they will fail that.
I don't know if we really have a complete and definitive answer, since Pixar may have enough talent to make these sequels good. What's more it might be that these sequels are a blip, and after them we'll get a rash of original characters and story-lines. On the other hand, this doesn't seem like a good sign.
When has Pixar ever disappointed? Their worst works are better than just about anything any other animation house has put out. Even their shorts are exceptional! As long as Lasseter and Catmull are running things, I have absolute faith that if they do create sequels, they will be stories worth telling. Because to those guys, along with Andrew Stanton, Pete Docter, and Brad Bird, the story IS what is important, and has always come first. Now, bring us a Lasseter/Pixar classic Disney character film!