err, 

scratch "consise" and read "concise" please.

I guess this system is better than the nimzo if you want to achieve a draw,
but not for winning against white's setup. On Super GM Level you have to know if they use the opening for achieving a draw or actually want to have some winning chances with black, look at Kramnik in the Wch, he played the petroff against everyone and was satisfied with a draw ...

(i)  1. d4 d5 2. c4 e6 3. Nc3 Bb4 4. e3! gives White a Nimzo-Rubinstein Botvinnik-pawn-roller system. White intends Bd3, Nge2, f3 and so on.  One point is that after a3, Bxc3 White can always dissolve his doubled c-pawns with cxd5. This line is good for White (and that's why you don't see players nowadays going for 1. d4 Nf6 2. c4 e6 3. Nc3 Bb4 4. e3 d5?!)
In Ward's QG book, Ward surprisingly acquisced to a transposition to the Ragozin with 4. Nf3, this is surprising because his main anti-QG weapon is the exchange with Nge2, and one would have thought 4. e3 is more thematic.

(ii) 1. d4 d5 2. c4 e6 3. Nf3 Nf6 4. Nc3 Bb4 (QGD Ragozin) 5. cxd5 (5. Qa4+ is also possible) ed5 6. Bg5 is the main line of the Ragozin, check Ruslan's ebook. 

(iii) 1. d4 d5 2. c4 e6 3. Nf3 Nf6 4. Bg5 tends to be a move-order to avoid the Ragozin, White usually intends 4... Bb4+ 5. Nbd2.

(iv) The purpose of 1. d4 d5 2. c4 e6 3. Nf3 Nf6 4. g3 Bb4+ 5. Bd2 Be7 is to avoid the main line Closed Catalan where White puts his knight directly on d2 and plays for e2-e4: e.g. 1. d4 d5 2. c4 e6 3. Nf3 Nf6 4. g3 Be7 5. Bg2 0-0 6. 0-0 c6 7. Qc2 Nbd7 8. Nbd2. White can block the check with 4. g3 Bb4+ 5. Nbd2 but 5... dxc4 is unclear and i seem to recall Markovich saying White has good practical compensation if Black tries to hold on to his pawn, there was a series of articles in NIC yearbooks on this but I've not read them closely yet.
 
The Ragozin is a respectable opening as any other. But White need not allow it, and Black seems too passive for my taste in lines (i) and (iii).