To be fair to Slurpuffs case, theyre based on different sweet desserts as Slurpuff is a Meringue and its pre evolution is a cotton candy while Acremie is cake frosting that will lose its gimmick in gen 9 or 10 anyway.

Wait, didn't Gen V introduced a whole slew of previous-generations expies? (Heck, Roggenrola is practically Unovan Geodude.)

Granted, you can still transfer the latter into the former but still.