The capture does leave Black with a backward pawn on an open file, which ought to be good for something...

It's not a terrible capture. Yet, it is not forced. Black wants to open up the game so that he has some tactical chances. Why give it to him? 15. h3 followed by Qe1 puts the pressure back onto Black. After the bishop trades with the knight on f3, White has an attack on Black's king-side. He might be able to defend, but it won't be pleasant.

agree, the capture leaves black has a backward pawn, and there is no reasn why the f pawn should be weak. whether taking the pawn or not, black's kingside lacks defensive pieces--white should have no problems

Maybe there was something to be said for allowing Black to exchange N for "bad" B on e3: 18...Nf5 19.Qe1 Nxe3 20.Qxe3 with Rae1, Qg3 and/or Bc2 in mind.

Instead of exchanging on c4, there was a lot to be said for inducing Black to exchange minor pieces, if that was his intention. One way was 22.b3 Nxe5?? 23.fxe5 and the BQ is trapped! If 22.b3 Nxe3 23.Qxe3 Nf5 24.Qd3 looks OK for White. More than likely Black had no intention of exchanging on his own account, merely to redeploy the knight to d6 thence to f5 or e4.

I have a feeling White has conceded more than she had to in relieving Black of his isolated e6-pawn. Note that in recapturing the way he did Black transformed a weak pawn into a strong one - the recapture with the c-pawn would still have left him with a backward weakling on e6. Preferable (for White) seems 25.Qd2 with some such plan in mind as Rae1, Qc1, Bd2 to bring pressure on Black's weak pawn. *** Having said all that, the diagram position shows White with somewhat the more mobile majority, though Black has rather the more active bishop. Prospects look fairly even.

It seems a little strange to have held onto your dark square bishop by refusing to exchange it for a knight earlier, while here you quickly give up the light square bishop. Because of the color most of your pawns are on (well, the central ones), the DSB is a 'bad bishop' -- it has no scope as you have in hemmed in, so it's hard to move around and can really only do some defense. On the other hand, your LSB is a 'good bishop' -- it has some nice open diagonals and can attack enemy pawns, or support a b2-b3 push if you want to break up the queenside ever. All in all, I think you got rid of the wrong bishop.

the exchange leaves white with a defensive position and a bad bishop, while eliminating the backward pawn--does not seem to be a good plan for white. It puts white unnecessarily on the defensive. A better plan would have been to retain the bishop.s, and prepare a kingside advance exploiting the 3-2 majority. With proper play, white would have been virtually a pawn ahead.

The e4-square is a fine post for the rook, and Black has some prospect of tripling the heavy pieces along that file. At move 27 White might already have considered 27.Rf3, ready to enlist the King's help in defending the bishop. Meanwhile, the a1-rook inhibits Black's advance on the Q-side. *** Having allowed the advance, possibly White could have allowed Black to take on a4 as well, with 29.Qc2, say.

A product of not having a follow-up plan (though this might well have been due to overlooking Black's 32...Qc6 reply!). In principle, Qe5 is a good idea for White. Maybe 32.Qe2 (or Qe3), 33.Re1 and then 34.Qe5 was a plan to go for.

It is becoming hard to find moves for White. 34.Qe3 might be worth a look.

at this point, the bad bishop and inability to mobilize on the king side is becoming fatal for white