Some cards are in some rulesets even worser at higher level, take the Gelatinous Cube, if you use Mimosa Nightshade or the Ruleset is "No Magic" the Gelatinous Cube level 9 is better than the level 10 version, simple because he has one livepoint more and Void is already added from the summoner or is not neccessary if no magic monster can be on the battlefield.