As the title says, it would be nice to have the transformations have skill points to distribute into as well. Why? Well if Kaio-Ken has them than why not transformations? I'll explain how this would work.
Obviously when you wish for the form you'll start at 1 SP and you'll be able to put 2 more SP into the transformation (giving the skill 3 SP total). One SP would make the forms have the vanilla stats. By adding SP you would do the following:
Super Saiyan: Slightly increase the stat bonuses and reduce drain; double EP buff and CD would remain the same.
Pure Majin: Slightly increase the stat bonuses and reduce drain; CD would remain the same.
Great Namek: Slightly increase the stat bonuses and increase form duration (12 minutes for 2 SP and 15 for 3 SP); CD and Dexterity debuff would remain the same. Also give the form a time indicator like a buff so players can keep track at how much time they have.
The decrease in drain in particular would give melee classes like Fighters and Grand Chefs an easier time maintaining the form due to their low EP while allowing classes like Turtle Hermit and Karma Majins a good option to use should you need the bonuses Kaio-Ken doesn't grant. At the same time though, the fact that CD will remain the same will still prevent these transformations from being spammed as well as give Kaio-Ken some use due to its 6 minute CD. Of course you don't have to contribute to the forms, especially if your role is more needed outside of the forms. Like Kaio-Ken, it is entirely optional whether or not to distribute SP to these forms. On a side note, Great Nameks and Pure Majins should also have their transformation-only skills unlocked at 1 SP when the form is wished for so players wouldn't have to waste SP just to get the skill.