You are playtesting this one too, aren't you?
I think using any number of cards lvl 0-2 from a sub class is a better deal than up to 5 lvl 0 from any other class.
Not necessarily. If you solo the game with just one investigator, you may want this or that card from another class to get some more variety vs great specialization. Or you may want to get an extra lvl 0 card for you deck because while campaigning you discover you need to boost this or that attribute and you need that card
Playtesters cannot reveal that information before products release.
Exactly, testers are not allowed to share their position as testers until the game's released