Currently, Ive noticed cards can have absolutely horrendous placements in your deck. For example, I was playing a US/French deck, and I needed 1 card to finish a combo. I had 3 copies, and I found that card in the last 6 cards. All 3 of them. Back to back. This happened a couple of more times, with all of those cards being in the last 20 cards in my deck. I have also noticed times where I draw 2 or 3 of a card in few turns, or I will get the sole copy of a card I mulliganed. To be put right back into my hand*
To be honest, it isn't a terrible issue, but I hate winning or losing a game is solely decided by wether or not I had bad luck or my opponent worse luck. For example, one of my opponents had 3 'from the mist's ' in his starting hand, or I've seen countermeasure decks that don't seem to draw any countermeasures. I still think that forcing cards to be more spread out through the deck will make lower rarity cards always easier to draw
To remedy this, force copies of cards to have a range of at least 12-15, so they are spread evenly throughout the deck. This could also be determined by the amounts of copies in your deck, with 4 copies having a range of even 20 cards.
For mulligan and putting cards into your deck, just make it so you can't get cards you dropped from the mulligan, at least cards with only 1 copy. Perhaps mulligan cards will be put on the bottom of your deck to make the choice of keeping a card more thoughtful
For fair hand mechanics, make it so the first card you draw for your hand be a 1-cost card. Sure it'll promote one |1 cost card| decks, but it will also make sure your enemy can't just overhelm you due to luck


