In the post story, definetly, in competitive battles and such, yes, and on the journey from 1 to 100, most definetly, the only Pokemon that has the 3rd form not their for the longest i Deino, but its not a starter, and is generally caught lv40. However, in the story from start to elite 4, you have the 2nd form for longest, the most Gyms definetly, but not in Kanto and Sinnih, where lvs are generally higher.