Yes: the Q at d4 is bad only insofar as a knight on c6 can chase it away - an impossibility if it has been exchanged off betimes. Otherwise, her eviction from that square is much less easily arranged...

I begin to think, you know, that the Scotch has this advantage when playing a much more experienced opponent: that it is not easy for the latter to conjure up any worthwhile complications this side of the endgame... not without considerable risk, at any rate.

a W1-D19-B13 record seems very encouraging record for Black!

Actually, I would have looked very seroiusly at that exchange line. First of all, what are the consequences of 12.Bxf6 gxf6 (i.e. Qs kept on)? I have to admit they look pretty good for White! With the Queens off, Black will have 4 pawn 'islands' to White's 2 - a considerable advantage to the latter, broadly speaking. Overall, White's pawns would be very much the stronger. In my view, the bishop pair on their own would not make up for this. Having said that, Black would have had a stronger hold on the centre. That might - just might - be enough to tip the balance. It is here I reckon I would have gone into a 'Big Think'.

The problem is that black has enough compensation after that trade ionadowman mentions and can quite effectively stop white from using these stronger pawns due central control and open lines. For example: If black plays pawns on d5 and c4 with rooks keeping the b-file then I don't know how white could break this deadlock. White doesn't want to play c4 as black will just trade d-pawn for that c-pawn so black can carry c4 plan. Black even seems to be slightly better there.

Possibly the attack by the rook on b8 might have something to do with it: 13.Qg3 Bxe2 14.Bxe2 Bd6 15.Qc3 Ne4 16.Bxd8 Nxc3 17.bxc3 Rfxd8 ... Though I have to admit Black's edge looks wafer thin to me. Having said that, it does put White on the defensive for the rest of the game, however good his drawing chances.

Consider this against the end position of the line I gave in my previous comment: White's doubled c-pawns. This looks very even to me.

Actually, 17.b3 wasn't forced, though it is hard, I accept, to contemplate moving the rook to b1. Yet that was probably the right move. The pawn move places all the Q-side pawns on light squares - the same as Whitte's bishop. Black's response pretty much at once exploits the weakening of the light squares. (I hate to enunciate this as a principle, though. Sometimes placing pawns on squares that your bishop can reach offers it a useful anchor. You have to balance mobility with the availability of safe squares. For instance, in this position, d3 might prove to be a useful square for the White bishop).

Well that is undeniable! Some good thinking has gone into this - and you are using the databases very intelligently.