the idea behind the 2nd point sounds interesting. but honestly, I think every other suggestion is not good at all. mit to say: devastive
for example, having 10 different levels in rpve is allready to much. who plays all these?
making the top wanted cards (those who costs the most) all rare would rise their prices even more. very, very bad.
droping every card from tier 4 to 3 would destroy the current meta (for sure, a new one will rise, but at which cost?). besides that, pve would get much easier. on second thought, you most probsply ment to change one orb to colourless. but which colour to take from cards like Lost Dragon? why do you want so much extra secutity?