I have never had a problem when the Mi-Go spawn, if you keep an investigator in London you can fill the board with clues and not be as hard pressed.

With 2 investigators it's hard to keep anyone in one place.

I guess I could try with 4, we're getting more comfortable with the rules and gameplay so each of us running 2 investigators could work.

Therein lies the rub, I have always played with 4 investigators. It doesn't matter if I am solo or with friends; it has always been 4.

I don't know, I love the game the way it is. Even "impossible" scenarios just add to the fun. It's like a huge puzzle. One wrong move and you've lost. Face it. You have at max 32 actions and 16 encounters to solve 3 mysteries and do a goodly amount of fire-fighting. It's a freakin' blast! I have a hard time explaining to people why I'm not into AH at all but I love this game. It wasn't the difficulty putting me off of AH it was just how random it all seemed. Say what you will about Eldritch Horror but things at least happen for reasons and it feels a lot more sensical and coherent by comparison.