And films have always been graded; this is just a (comparatively) new way of doing it.
And considerably uglier.
Many films were badly graded using the old photo-chemical procedure, many films have been beautifully graded using a digital intermediate and, obviously, vice versa.
Have you got any examples offhand?
This is probably going to lead right into another comparison of in the end subjective judgements, based mostly on personal preferences. If, say KING KONG is mentioned as a positive example of digital grading, in the end it really depends if one likes that artificial sepia look or not.
I think there is a more objective way to gauge this technique, even for the likes of laymen - and only mildly interested ones, at that - such as me. Colour grading has one simple and comprehensible task, matching shots and evening out differences. Going by that I'd say it's possible to judge the technique and its results on an impartial basis. Are there a lot of shots that don't seem to match, that don't pick up the right light or atmosphere or just seem 'odd'? If so, it's probably justified to call it a failed job, regardless of traditional or digital procedure.
The other task of colour grading, the subjective goal of creating a particular look, could be examined insofar as one could question the original intention and decisions based on this (is that look the 'right' one for the film?) or the outcome (did they succeed in their aim?). It's still an opinion-thingy, but it's perhaps a little easier then to understand why one arrives at this or that.