Oh gosh, sorry for a slow reply! For some reason itch.io doesn't give you notification for project comments! I hope you still get this :)
Yes, that's intentional. Two playbooks have higher attributes - Destined ( 5: 2/1/1/1/0) and Lead ( 4: 2/1/1/0/0).
Destined get it, because their feature (Flaws and Visions) gives GM a more direct control over the character and Flaws make their game harder no matter the stats. Them being GM's plaything, will be even more apparent in 1.8 release, which is coming in the next couple of days. Also, unlike everyone else, Destined don't get a 1 to attributes or any other unique bonuses (Stamina, Rings, Armor etc) via their regular improvements (only get 1 Advanced), so they don't have as much growth potential as the others.
Lead funny enough have the opposite idea, as they are supposed to be a more generic and basic "fighter"/"hero" type. A Power Fantasy if you will. So I gave them a 1 and they are technically the most raw powerful playbook via pros/cons. Their Feature was also made to help the group, as a Leader, basically sidelining their stats. I recently thought about it and in the 1.9 release, I'm planning to basically remove their current Feature and making them a more classic "Solo Sonic Hero", which should make their Feature the most "boring" one of the list, to offset their really good stats.
And everyone else should have a 3. If they don't - that's a typo :)
TL;DR: Not balance then moves, but to balance the Features. This game's originating design philosophy was "I really liked Monster of the Week, but I want more playbook moves."