3 Bd3!?

Something similar to this, but without the extended Black queenside

?

This looks good

Although it's passive

Who plays 6. ... Nxd5?

One point of 5. ... d5 is to open the d-file onto that loose Bishop on d3. You play 6. ... Qxd5!

The main problem with 3. Bd3 is that it makes no sense without also playing c3 followed by Bc2 and d4... but this is TACTICALLY faulty because as soon as White plays c3 Black will answer with d5 and then recapture with the QUEEN, not with the Knight.

You don't ordinarily put your Queen in the center like that, but White's c3 move rules out Nc3 and makes the d5 square quite a comfortable spot for Black's Queen.

Oh

I actually thought of that but didn't realise what it would do after Bc2

After Qxd5 and Bc2, how is White going to play d4? Black will have at least FIVE pieces covering that square (after bringing a Rook to d8).

What is White going to do if he CAN'T play d4? Leave the Pawn on d2? How does he develop? Push it to d3, where it is backward on an open file? What is that Bishop doing on c2, then?

How does White develop after Qxd5?