1) drop rate of the boar is so low, it defeats the purpose to even participating. energy be better use in the arena.
2) drop rate of coal is so low, even on the highest level. you get many stacks of rubbish ores which you can’t use or throw or sell in bulk. since you can gather without energy, it would make sense to do this now and then. also crafting item to sell can also be an incentives. you should be allowed to choose the ores you want to find by ignoring the others.
3) upgrade item should require certain ore and thus, reduce amount of silver needed if you have the required ore. certain upgrade ore can find be found randomly through gathering.