I liked two things about the film: 1) What the animators did with snow and ice is nothing short of miraculous. 2) Olaf's song about enjoying summer is clever, amusing, musically appealing, and well-situated.
I read a number of critic reviews--positive, negative, and mixed--this morning to see if they had the same feelings, and I'd say I was more or less on the same page as many: frustrated by the rushed and nonsensical plot and shallow, weak characters. It was like Disney tried to make a modern classic by stealing and somewhat-twisting tropes from their actual classics, but utterly failed to tell a compelling story--visually, musically, and verbally. The song lyrics were either shallow or morally and didactically heavy-handed. Many times the dialogue either didn't make sense (I could not make heads or tails of the character motivations) or served to do what the visuals failed to: a good film (heck, good writing) shows rather than tells, and I felt that the film erred in telling more than showing. What tended to be a real strength in Disney classics--setting the mood of the film through careful use of colour, light, line, shape, etc. as well as musical accompaniment--was much weaker in this film (this is an interesting post that touches on the limitations of 3D CGI in capturing character). The whole movie felt very surface-y as a result.
Of the reviews I read, I most enjoyed Dani Colman's The problem with false feminism (or why “Frozen” left me cold). Check it out.
For my film study requirement for my grade 10s and 11s, I've been contemplating a "Deconstructing Disney" unit to help students practice visual and aural literacy.