It's impossible to get an outbreak until the first epidemic has occurred.
As such the placement of the first epidemic in the player deck has a large effect on the game. If near the bottom, it allows the players to go through several turns before the game starts become risky. At that point they may have already cleaned up most of the disease cubes and largely mitigated the risk.
Now of course, having more epidemic cards in the deck increases the chance that one will be near the top. Also - if one isn't near the top, then it means that there's a higher concentration of later on.
However this does still seem like quite an unkiltering dynamic of the game, where a large amount of how the game goes is down to luck.
The question is - does this dynamic have a significant effect on the game, and how can it be mitigated?
One option I've considered, is that you might shuffle all except one card into the player deck, and then take the top 10 cards off, and without looking, shuffle the last one in. So there's guaranteed to be an epidemic in the first 11 cards.