The picture is DWA's summer release, and Scott Mendelson at Forbes is bullish:
... The original How To Train Your Dragon earned $494 million in 2010, a fine sum but less than even the likes of The Croods ($587m). Ten years ago Shrek 2, a well-liked sequel to a popular and leggy original, shocked pretty much every box office pundit and grossed $440 million in America and $916 million worldwide, or basically double the original film’s $440m gross.
Last year Universal’s Despicable Me 2 pulled the same trick, earning $970m off of the original’s $543m. Of course, it’s possible that the film will play like Cloudy With A Chance of Meatballs 2 and earn just a little over the original’s worldwide gross (think $550m), which would still make it a hit compared to its $165m budget. ...
I'll go wild here and say that Dragons 2 will do way better than Meatballs 2.