Firstly, you are not the only one who thought you were watching Tabu! Me too.
What I really liked about the film was that it does not glorify Devdas. I doubt if Sarat babu himself portrayed Devdas like what has been shown in countless versions. Bhansali aided by SRK' iconic status took this to new heights. Or lows, whichever way you want to look at it. I definitely want to read the novel now. All the more because one of my friends who has read all or most of Saratbabu says, - if Sarat were to see Dev.D he would have said, "finally someone has understood what I wanted to say".
The Devdas who cuts a sorry figure has become a metaphor in Indian psyche. How many unshaven, unkempt, dumped-by-girlfriend college youths have been asked by their friends this question - why are you going around like Devdas?
As you come out of the movie hall, you don't feel sorry or remorseful for Dev. Far from it, you almost want to give him one tight slap and ask him to get on with life.
I was glad the women have moved on too in Dev.D - so no more of Paro running around the haveli (or sugarcane fields, if you like) with her pallu streaming behind, wailing loudly - Devaaaaaa

I saw the movie over a week back and it refuses to leave my thoughts still. Not many movies have done that to me. I finally wrote on my blog about it so don't want to repeat it all here.
Just one thing - I don't think the blue-red man is not just 'Director's eccentricity.' On the contrary, I felt it provides a reinforcing compliment to Piyush Mishra's character (Prithvi Bana.) Prithvi is a counterpoint to his aggressive firebrand brother Dukey Bana and constantly ridicules him with its scathing wit. I kept thinking that both Prithvi and this character are representing Dukey's struggle with his own impotency, which he is very aware of (but can't show it to anyone.) Dukey goes about spewing venom in his speeches and bashing up Madhuri (Mahi Gill) because he probably knows that he can do little else.