I'm personaly absolutely loving this year of MLB The Show.
There's no variety in cards? I can't disagree more... I have so many very good cards right now at each position, that I really don't know who to start first, this is great. And we still don't know, what cards will come in Set 2.
I also don't know, what is that strategy in team building OP is talking about? I played lot of MUT, HUT and Fifa before and I don't see any strategy in team building there. You just use the best cards available to you by grind or money transactions, that's all in my opinion.
The true difference between DD and other Ultimate modes is in the quality of cards you can grind for free. And this is much, much better in DD than anywhere else