You definitely need a prepared response for 1...e6 from black. After 2. d4 f5, you are in a Dutch. After 2. e4 d5 you are in a French, and you've already committed Nc3 (meaning no Tarrasch, etc.). I prefer the Two Knights variation, e.g.:
You would do well to have some ideas for the d6-g6-Nf6 systems by Black, but in my experience you have a little more elbow room in those cases. It would also be ideal if your choice was consistent with your Veresov Attack against 1...Nf6.
Your move order might pack a subtle advantage against some Benoni-esque systems because the c4 square is free for your other knight, instead of being occupied by a pawn:
On a personal note, I feel like you are missing out on the real fun of the Van Geet opening (the independent lines after 1. Nc3 d5 2. e4), but as long as you are happy then it's all good.
I was trying to come up with a solid repertoire for white, that was not overly used or analyzed. So I thought up something based on the Van Geet opening (1. Nc3). Now, this is a hypermodern move, but that does not have to be the case after move one. My idea was that, after 1... d5 or 1... Nf6, I play 2. d4, transposing into the Veresov, a solid opening. After 1... e5 or 1... c5, I would play 2. e4 transposing into the Vienna game and Closed Sicilian respectively.
So, any thoughts on this? And are there any other first moves I would need to be able to respond to? Thanks.