How to keep a feeling of challenge and excitement?

What to get for the person who has everything? A little something to combat the ennui?

How to create a campaign that gives a good level of difficulty plus a good quality reward...

Challenges are good, but bad for long-term play since they aren't really useful unless you have a broad selection of fully leveled up cards. And even still, you can only play through to get Elite II if you manage to complete the Nightmare mode. This is not very good for new players, who might be able to complete the normal mode the first time they encounter a challenge, will probably have to pay to complete expert mode on the second challenge and probably won't be able to even consider completing a nightmare mode challenge for a few months. Even if you can, you'll still be unable to use your new rare card for much of anything since it will only be Elite II or maybe III.

Which will put the player back to needing to rely on cash and the cycle of grinding that is to be avoided.

Even with the hack enabled, it can still be quite difficult to push through a challenge because you need to build up those levels.

2.0, anti-hacking and why you might want to just hold off on that epic update.