Do something similar to other games. Have a 'easy/normal' mode for those wanting to blow through GW and get something, but not spend a ton of time. Then have a hard mode with stiffer competition and bigger rewards. You choose the type (easy/hard) before node 1 and have to stick with that until next restart of GW. Pretty simple in theory. Just requires one extra launch page and getting an algorithm that works for picking opponents and dishing out rewards. Hard would possibly mean not completing GW also if facing maxed teams at the end comparable to your team, but most likely stronger.
I'm sure this has been given as an option before...just haven't seen it myself.
