This might be controversial but….
I never messed with the idea that aang had to specifically let go of katara to master/be able to enter the avatar state on his own. To me, it just didn’t make a whole lot of sense that it was his love for katara keeping him from going into the avatar state at will. Furthermore, it always made me think “oh so his love for appa, the air nomads, & sokka was weaker than his love for katara?” (Actually it makes sense he’d love katara more than sokka lol)
It’s also part of the reason why I really enjoyed NATLA establishing that he can go into the avatar state at will, but he will have less control over his actions until he masters all the elements. This is not to say I think aang shouldn’t have a strong attachment to Katara, Infact I’d be pissed if he didn’t. It’s just his love for katara shouldn’t be the lock on the proverbial avatar state door if that makes sense?
Now despite me loving the stuff they did establish in the finale, I do think the astral aang stuff kinda had less of an impact because of the lack of the guru, and I feel they could’ve done something else to give the scene more weight narratively speaking, but I’ll take what I can get lol. It’s also why I think NATLA would’ve benefited from keeping the 8 eps so we wouldn’t run into these types of issues.
But yea, this is just my quick thoughts. What do yall think?