If you run with the last official release, then a champion only player will count for around one-fifth of a normal player in terms of wave multipliers and the like. Manageable.
If you run with the latest beta update, then wave increase is gone, but the AI will have a champion countermeasure of their, requiring you to pay a bit more attention to defense. The next version will delay that a bit further, but otherwise... If you've grabbed the latest update, use some of the extra starting resources you're given in order to make certain your HW is secure.