I don't play 1.d4 or the slav so probably wait for someone else to answer more definitively.
But just looking at some GM lines what I'm thinking is, first of all, dxc and then black trying to keep the pawn with moves like b5 and a6 is a well known slav line (even to me). And the two moves Nf3 + Bf4 do nothing to combat that.
If the moves are instead Nc3 and Bf4 then it makes a little more sense because at least Nc3 is part of fighting back on the queenside. And of course if black promises not to capture on c4, then Bf4 may even transpose into some kind of Bf4 queen's gambit (if black plays c5 later). In other words there's no grand strategic idea that makes Bf4 a bad square, it's due to concrete reasons.
Hello!
I have a question regarding a move that seems logical but according to the database is almost never played in the semi-slav opening and in the slav opening as well for that matter. And that is the move Bf4 for white.
For example here:
Or here:
I've encountered this move many times when playing on my level of play but I'm wondering why it's almsot never played by strong players. It seems like it's a good diagonal to develop our bishop. The main move is Bg5 or e3 for white.
Cheers.
Sorry for the mistake in the title, I meant Bf4 of course.