Scotsman wasn't tacked on because Scotsman was great, and the episodes he starred in were well structured around including him.
That's not really the case with Ashi, so far. People say that she's supposed to help Jack, but he was doing an alright job of helping himself out of his slump if you ask me. Instead of Jack getting a proper arc fleshed out over the course of the season, he has to share time with Ashi and her arguably even more complex problems. Chances of them both having satisfying development are low. Genndy is good, but he's not a miracle worker.
Plus all this crap really fucks with what I chiefly liked about Jack in the first place, which is his loner aspect. It's not because I'm forever alone and sympathize, or because I think it's edgy and cool, or whatever Ashi detractors are labeled as, but because I admired it. Lots of stories, especially ones geared towards children, really put a lot of emphasis on relationships. You know, the power of love and friendship and shit like that. That's fine, relationships are important. But for Jack, he was largely alone, with his friends being few and their appearances far between. He got by on his inner strength and forged his own way through his challenges and enemies and obstacles.
So this Ashi shit really does cheapen things for me. It's looking like they'll lean on each other and heal each other and learn from each other and all that good crap that you can find nearly anywhere else. Sue me for wanting a story about Jack finding his own way back to the hero he was and finally accomplishing his mission. Independence is an important lesson that everybody needs to learn.