-_-" the point is you would get your buddy.... which means you get more health, which this suggestion takes away one of the main points of the buddy (you and your buddy have your own health bars, ki, stamina, and pl and you would be able to switch between them when you like), and you will be able to use new team attacks to do more damage. A speed boost has been discussed but nothing final yet. Remember Ginyu has that special dirty attack of his too D: personally i think thats enough of a speed boost if you use it on the right person successfully.
Its pretty balanced against ssj3 goku when you're able to switch between 4 different characters to fight with, all with their own moves & pro's/cons/stats, and able to... turn the situation around.
I'll repeat it again though so people understand, Buddy's are a replacement for transformations.