Here's an opinion from an eminent film critic on TITANIC, back when it was available in 2-D widescreen (blown up to 70mm for select engagements) on its original release in late 1997:
Pauline Kael on TITANIC: "It's square in ways people seem to have been longing for. I'm not one of those people."
Ms. Kael's quote was from a NEWSWEEK article about TITANIC-as-phenomenon.
Here's hoping that, as David Edelstein mentioned in his recent NEW YORK magazine re-review, the addition of 3-D is the magic improvement that heightens the spectacle while decreasing the too-on-the-nose, tin-eared dialogue that James Cameron gave to his characters.