Blackjack is an insanely simple game to program. The way the game is played is quite simple, as there is very few choices for the player to take.
All play is between the player and the dealer, any other possible players don't matter, and the way the dealer plays follows a strict set of rules, which makes the AI very simple as well. Even if you still wanted a couple NPC players just to look good, you would only need to either do near-random play, or use one of the known ways to beat blackjack (which a bit of reading will give you an exact set of rules to follow). No real thinking is needed by AI in any case.
IMO blackjack is a simpler game to write than tictactoe, which is often the first game people write...
As for making it "feel deep" and "like everything is on the line" I don't know what you are talking about.
When you get down to it, the only way for a gambling game to feel "like everything is on the line" is if everything really is on the line, and even then a lot of people just can't feel it (think: addicted gamblers)
Shoot Pixels, Not People.