1) You can count basic value roughly as card's realtime [health] + [attack] + [ability value], for example [Big Game Hunter](3 cost 4 atk 2 hp), the basic value of it can be calculated as (4+2), but if enemy has minion with attack >=7, then its value is (4+2+7), if my battlefield has minion with attack >=7, then its value is (4+2-7).
A card's value is very situational, hearthranger can deal with all situations correctly, only if it's not good (for example not good timing, or too waste its value, or can have a better combination with other cards), then you can set deck rule to control it.
For bot to play good, I think there is no need to set too many deck rules.
2) I'll add a new condition to solve it when next update.