Yeah, she's in a perfect middle ground.
I also LOVE the decision to make her a guidance councellor.
That scene where she cheered up Twilight was golden, and illustrated what Starlight brings to the table.
Twilight's friends were focusing on cheering her up or patting her back in sympathy,
which is fine, but Starlight said "actually, I'm going to tell you what you did wrong." and it solved the problem.
Just like in the episode "A Royal Problem", this approach is sometimes the right way to go.
Starlight can cut through the bullshit and address the heart of an issue, which makes for a useful alternative method.
The scene also showed how well she's come to know and understand Twilight's personality,
which makes perfect sense considering that they live in the same house together.
There's also the fact that the mane six's dynamic is "being friends despite being completely different ponies".
There's still gonna be a "limit" to how deeply they can relate to or understand Twilight.
Starlight has much in common with Twilight, so that would make it even easier to surpass that limit.