Eternal is 4x card limit. I believe they went with 75 to force more variance in deck construction. I wonder how 3x/60 min would have felt.
I argued for this exact thing many times in multiple threads on the beta boards. It would have achieved their desired effect of more variance in how games play out, without increasing the chance of screw/flood so much. The aggravating thing is, we never got any kind of response or acknowledgement from the dev team about it any point. It's one of the main reasons I stopped playing it at the time.
As for my 'guess', not exactly. Myself and others once ran the numbers for one of the threads about this on the beta boards, I just don't have them available anymore. It was close to 10% of games, but I was being conservative since they did add a handful of things that should have helped. Such as power cards that have a small effect (gain life, make a 1/1, etc..) if you already have 4 of that influence in play. They have a very, very minor effect overall, but it's a step in the right direction at least.
Its mulligan rule isn't that great, you get a one time only mulligan and it gives a min of 2 mana only from a deck that gets a one time shuffle.
Enzee
I'd say draw/tutor/library manipulation in eternal is reduced by 3/4 compared to mtg, there is barely any and most of it is subpar at that even. I'm still amazed by some of their poor design choices still, just like the recent nerfs that happened.
Yep, the mulligan isn't really that great. Once you realize you only get a single mulligan, no option for more, it's not all that much better then paris mulligan rules. In mtg, you might get a hand that is '3 mana, 4 spells' and yet you know it wont win the game and ship it. Getting a 6 that is also really bad happens and then you might go to 5. If your opponent also went to 5/6 cards, you've still got a good chance to win. That doesn't happen in Eternal, you are stuck with that 2nd hand, even if it's got 3 of the wrong mana for the other 4 cards. It might be technically a good mix of mana/non mana, but it's still a terrible hand. Then, you might draw 4 more of the same card type in a row and just lose as a result.
Also, yea, I was being generous on the 1/2 estimate as I haven't played mtg standard in the last year or two. Compared to standard formats I played, it's like 3/4th less, but figured maybe there isn't great tools available currently.