Hello,
Thank you for your feedback!
I hear you about the XP-to-health ratios. Right now you can get more xp mining stone rather than iron (until your damage gets too high). The idea behind the health/xp ratio is to try and give you a reason to mine each rock instead of 1 being the best one. Ex: Iron gives more money but maybe tin gives more xp. Just some insight into my thought process. The game is very early in development and will be rebalanced as features come out so this is something I will definitely be keeping in mind!
Thomas
boxedworks