Uh, "spontaneous" and "over a year and a half buildup" simply don't match.
Also, him beating up Kurama is also arguably part of it- it established himself as someone Kurama had to acknowledge in terms of power, rather than just overwhelm whenever Naruto's guard got low.
And the parents thing? Remember Minato wanted Naruto to have access to Kurama's power and his and Kushina's legacy included the desire that he gain mastery of it and protect the village.
Not all build-up to friendship has to be nice.
Plus Naruto's recent developments ruined what could've been an awesome momment of Kakashi and Gai being blasted.
That would've been pretty bad writing if it did...
I mean, if you get consistently disappointed that wildly out-of-genre things don't happen, the problem's probably on the side of your expectations.