I wouldnt compare current kurama to other bijus.
The reason is that its not full kurama but just yang part of it.
Now this means that its not complete and needs some yin part to mix with.
Here naruto comes into play.
KCM BM states of naruto is actually a result of kurama's yang chakra.
In fact it enhances naruto's abilities to new levels (i think minato was aware of it). To form TBB naruto's yin chakra is also needed.
The truth is compared to other bijus kurama+naruto is much stronger now. I believe that if yin part was to return then this enormous enhancement would be cancelled by yin and yang balancing out in forming real kurama.