I wonder if the writers just don't like the Johto starters in general.
Typlosion has hardly any screentime in the anime, only appearing in the Raikou special and in Flannery's episodes back in Hoenn.
Ferligatr got a few more appearances, but honestly not much.
Meganium had quite a few appearances, but we've seen far more Venusaur owned throughout the show
Anyway it does seem odd. HGSS was supposed to give the Johto Pokemon spotlight, and it didn't really do that. Even Dawn's Cydnaquil got minimal role in the Grand Festival, not even getting a full battle.