The game changes with more characters, this seems to be by design really.
Yes with a small number of characters the blessing deck isn't usually the real clock - the real clock is the character deck. With a large number of characters the blessing deck becomes the clock - and the character deck less so. In a 1 character game that character could take 30 turns, in a 6 character game each character only takes 5 (assuming no deaths). This makes the game significantly different - you need to be trading cards in your character deck for cards in the blessing deck - which means playing "discard this card to explore" cards a lot. Whereas in a single character game some sort of healing to get discarded cards back in your deck will be very useful.
And sure some monsters become much tougher when there are lots of character - then again each character can add a blessing to the check.
The physical game is pretty well known for being more difficult with more players. It's just how it works