Farming shards is something Plarium would never do because then nobody will buy shard packs. But even putting that aside, shards should be a special reward, not something you can farm in my opinion. Having tokens for summoning is also something they would not do because they want players to get the same champs. Once they have all of them then there's no reason to buy shard packs, and this would conflict with 10x events. Personally I'm kind of mixed on this idea, because it would be nice being able to target specific champions you're after, but then where would we get this new token? For every resource added to the game they either have to replace it with something else or make new content which will require more time farming. This could also backfire by you getting a bunch more dupes, but with the dupe system implemented, maybe that wouldn't be such a bad thing. As for your last idea, I think that doom tower does this fairly well. The secret rooms and bosses in particular require you a certain team to win and their own unique mechanics. And with each floor you clear you are getting quite a variety of rewards. Then there's also the Hydra, which albeit, is only for endgame players, has added a lot of new mechanics, 2 new gear sets, and a challenging fight, so I think there is already much to do in this game and adding more would only increase the time we have to play.