I don't think I would have to do any adventures. I counted that collectibles and my explorers will probably cover the whole event for me and the 10 cake achievement if I can trade even with the 2:1 ratio. I will still do some because w have a community event and I can help guildies.
Again for the balance, we at higher levels have all skills unlocked, a lot more generals and explorers, we have access to 1d premiums for loot bonus, and so on. BB did explain the boost and balance at test: https://forum.tsotesting.com/threads...ll=1#post49415