It is clear that for a Jinchuuriki to master thier power it takes years of difficult training. We see even someone as skilled as Gaara has not fully mastered his Tailed beast form and simply represses its power.
Its hard to gauge the 2 tails and 4 tails because we are left out of the majority of those fights. However the Databook did say that Yugito (2 tails) went thru some difficult training she hated to control her power.
The 8 tails is porbably the most skilled Jinchurikin we have ever seen and obviously even he continues to train regularly to maintain his amazing control of this power.
So I started thinking how exactly do Jinchurikin learn to harness thier power and I couldnt help but think of the show Bleach. Maybe the realtionship between Tailed beast and Host is kind of similar to Shingami and thier Zanpakto in Bleach.
The Tailed beast inside is not just a tool or a weapon it is alive and a self aware entity. Perhaps the Host must make the Tailed beast inside respect him/her before they can work in perfect harmony. In Bleach the main charcter Ichigo had to communicate with his inner Zanpakto before he can learn to master its true power. When Ichigo started to doubt himself the inner Hallow powers started to take control over him rather than him using them.
I'm wondering if maybe something similar applies with Tailed beast and the reason Naruto cant control the fox is simply beacause the fox looks down on him and the minute it has the chance to take control it does. So the only way for Naruto to control the Fox is go on some kind of inner spiritual journey and get the fox to respect him so they can work in total harmony.
Well thats the rough idea so post you thoughts.