I love this entire idea you have here, Emu! However, while it may make items to get easier with such high rewards, I think we should probably lower it just a tad (maybe only gold?) since a majority of actually hard quests are only worth gold. Plus, if a quest is worth diamonds, normally they would not be repeatable since the reward is so high. This way people can have a challenge they want so they will not become bored with the game. :3 That way they will still be able to have the fun adventure of getting hard-earned medals and being satisfied because they worked so hard to get it and be satisfied with their reward!
If it were so easy to get medals with these quests, people would start to take it for granted and they wouldn't be as excited when earning medals and buying a pet or shard they want. I myself have been playing since early March 2014, and when I got my first gold pet, an adult dragon, it took me a while to get, yes, but when I finally DID get it, it brought me sort of a giddy, happy feeling, it made me feel proud of myself that I could get such an interesting and unique pet! I feel as if we make it so much easier to get gold, diamonds, and rubies, people will not feel the same way when getting a pet, and it would sort of defeat the purpose.
But trust me, overall, I love the ideas of new quests, prey, maps, and characters!