In 7-card stud, as Mythosx pointed out, I'd think the probabilities are easier to calculate than in Magic...
If it helps - I was thinking about Texas hold 'em all the while... which is a whole other ball game...
In Texas Hold 'em Poker - there are 7 base sets of probabilities... As each player folds from the hand, the probabilities change, and unknown components get thrown into the mix because the folded cards, could be cards you're needing, or are hoping to be in the deck to better your hand... you can narrow down the types of hands they'd throw away - no pairs, lows, off-suits, etc... but they may have thrown away high-lows, suits, and the likes, if the "pot" got too much for them to risk it on...
I still think there's more exposure in Magic during the first game, than during the hands in poker...
Land drops say a lot, spells, and permanents speak even more...
The formats in Magic tell a lot about the deck you're sitting across from... and automatically make it easier to decipher what you may be up against after the first few turns... Especially in block and sealed, if you know your cards... as for type 2 - It's scopes are limited, and most of the time, you face certain metas, in all Magic formats... if you know the decks in scene - those early drops tell you what you can mainly expect...
But you can't have that certainty when you only know what 2 cards are out of a possible 52... which is the first case in the poker hands... In Magic you start with 7 out of 60, normally, and you already know what the other 89% of the cards left in the deck are... for you... you see the rest of the cards as you draw them... In poker - you only see 5 out of the 52 cards, most of the time... and have no idea what's left in the deck for you...
I hope some of this made sense...
