Think about it. When somebody would meet Kabuto, he would just use Edo Tensei to summon their best friends. Lets make a match-ups.

Naruto vs Kabuto - Kabuto uses Edo Tensei to summon Jiraiya/4th and Naruto wont fight against Jiraiya or his father.

Sasuke vs Kabuto - Sasuke will cry watching Kabuto controlling over Itachi, and will start to beg him for making Itachi alive again.

Kakashi vs Kabuto - Kabuto summons Obito or Rin.

Madara vs Kabuto - Kabuto summons his [Secret Creature]

Tsunade vs Kabuto - Kabuto summons her Brother or Boyfriend.

So for now, he can rule over everyone, until Edo Tensei has any limits.