1) its not so bad like you think, try to calculate it. if you have low level you either have low HP and spirit, then better for you is to buy food and potions. but when you are level 30-35 or higher better for you is to buy 1 diamond on market and buy 1 rejuvination potion than all this potions to regain HP and spirit. its much better to do like that. and you have to remember you earn a lot money on those levels.
now if you are on level ie 10 and you have not so much diamond, maybe 3-5 from quests, then you can buy few rejuvination potions and sold them on auction for gold and make profits
2) weakness is changed but it still is great "weapon" for mystic. when mystic use weakness on enemy and this enemy strength drop down to 0 then enemies chance to hit either drop down to 0%. he dont make any damages till end battle
3) few examples:
- you go to zone where chance to dig is "certain", its 100% chance to dig, you use time multiplier x8 (bonus to dig is 75%) then:
100%*(1+75%)=175% chance to dig
- you go to zone where chance to dig is "less likely", its 10% (for this example) chance to dig, you use time multiplier x4 (bonus to dig is 50%) then:
10%*(1+50%)=15% chance to dig
radooo you can be attacked by other players only in danger provinces, and only in zones, not in town or in travel, you went to this zones on your own risk. you still can travel and buy potions and other items in shops without risk