Full Kyuubi was just to hard for Naruto to master.
Madara was capable to easily control the full Kyuubi Kurama,so it would not make a difference in power for Naruto,besides sealing the full power of the 9 tails is physically impossible for a baby to take that demon inside it.why didn't MINATO sealed full kyuubi inside Naruto
if he sealed whole nine tails then Naruto would beat madara easily
is it right or wrong
Full Kyuubi was just to hard for Naruto to master.
The reaper death seal reached a limit at half the kyuubi chakra, also a balance had to be kept, and kyuubi was needed for that. ,,,,,,and he had to prepare naruto to face madara (obito)