I agree with you as far as them maturing first (and the plot aspect. I need more Shima). Shiemi is still stunted in the love department, so for her to just enter into a relationship without understanding what that implies would be a disaster. And I like the pace at which they're developing too, so I don't want anything to be rushed. I can understand why people who don't ship them wouldn't want to see them have anymore moments, but to be honest, I'll be miffed as hell, if Kazue just let it fall to the wayside after how far they've come. It's way too late in the game to write their feelings off, especially Rin's.
It'd be equivalent to what Kishimoto did with NaruSaku, only to have them end up with different people, even though neither of the other pairings didn't have nearly the amount of development as them. And I don't ship any canon pairing in that disastrous story (except Shika/Tema). Only difference is that Kazue actually knows what the hell she's doing. For the longest time, I swore up and down that Shiemi and Yukio had a thing until Ch. 74, when Yukio verified that she liked Rin. That's a red herring done right, imho. I just want to see how everything will play out.
But I do still want the story. I need more Shima in my life, and I am curious to know how far Bon's training has taken him. Hell, I wanna know what they were all up to while Rin and Yukio were on their rescue mission. With a little ship teasing too (I hope Izumo and Paku talk with Shiemi; I never get enough of them).