What can Sabine really teach him about it though? She didn't know much about it herself and she didn't carry it that long. Seems like Moff Gideon could teach Din Djarin more about it than Sabine.
Well, Gideon fought once so far, and lost the saber. Sabine fought a stronger, more experienced warrior in a full duel with all their weapons, and won.
From a real world standpoint, she didn’t have much time with it... but from an in universe perspective and in the episode focusing on her learning to use it, she had a pretty intensive two day training with it, justified on the basis that while she knew how to fight with a sword, a lighstaber is different in some ways that apparently are very physical, and with an implication that some other ways could be physical extensions of a mental state.
Kanan and Sabine both confirm it’s heavier than expected for the type of weapon, with Kanan reminding the audience that a lightsaber is a current of energy instead of a physical blade, and spouting some info that claims your mental and emotional state impacts the blade, thus the ambiguity about how much of that exactly was true. I mean, kaiburr crystals are implied to have some genuine interaction with their builder and wielder, so the idea that even a non-Force user could impact their blade’s usage *might*have genuine merit.
In fact, that’s sort of my head-canon explanation for Gideon’s loss to Din; Gideon hasn’t been trained in the more esoteric principles of the saber, and thus while martially competent, isn’t quite as proficient as he needed to be.
But beyond that...
About the only thing I want from Sabine to give to Din Djaren is a coat of paint.
Sabine’s a pro-Jedi, pro-Republic Mando with her own history with the Empire, and who’s still holding on to Ezra’ saber. The latter fact would be an easy excuse to have her still be martially proficient enough to train Din in using it... but it’s the former stuff that I want.
I want someone to be the “white hat” Mando, pro-Democracy and more conventionally heroic, that Din ends up having as a counter-example to the also different authority figures of Bo-Katan and the Armorer.
The story would be best realized diving into the grey moral areas of Mandalorian culture... but you actually need some of the lighter and more traditionally heroic Star Wars morality thrown in to really make those stand out. Sabine could bring that different perspective to Din’s world, even briefly, and that’s far more valuable than just the fanservice of the two meeting.
Din needs to hear someone offer some balanced ideals about the New Republic and against some of Mandalore’s traditions. Sabine can do that, and speak with some authority on the subject that Bo, the former terrorist, and the Armorer, who pretty clearly seems to have served Maul, can’t.
And while Rebels was uneven at times, Trials of the Darksaber is a genuinely great bit of Star Wars, and I doubt the imagination fo anyone who doesn’t see the potential in trying to make a spiritual sequel to it with Din in Sabine’s place. I mean, Din doesn’t have a reason to want to be Mandalore yet, and has lost what purpose he had for two seasons.
Sounds like a perfect set-up for a sparring match that’s part physical practice and part existential crisis.
...Plus, they both have claims on the saber, so there’s some political subtext that can be mined there as well.