He can definitely deal with Mama Leung. Mama Lipinski was turned away by Doug Leigh, whom I've always thought of as a tough coach cos she was too tough! Then, when Richard Callaghan took over, Mama Lipinski basically just took to watching practices.
You know, the more I hear about Richard Callaghan, the more I like the idea of him coaching Mira.

Another thing I remember about when Lesley Hawker first started training under him, not only did Richard improve Lesley's skating technique, he also kind of gave her a makeover (getting her to buy expensive makeup, dyeing her hair blonde, etc.) Which is another thing, as petty as this sounds, Mira needs to work on.
As for a coaching change for Joannie, a couple of us suggested it might be a good idea for her to return to Sébastien Britten and the other coach (whose name I can't remember) who worked with her during the 2004/05 season. That was the year Joannie got her 3-lutz consistent, first landed 3-3s, her artistry improved by leaps and bounds, and she really started to break out on an international level.
I understand Joannie's reasons for returning to her old coach, but didn't Joannie's old coach originally "fire" her because she felt there was nothing more she could teach Joannie? Joannie always seemed to have a great relationship with Sébastien (remember all their high-fives after every competition that season?) and the other coach, and I hope they'd be willing to take her back if she wanted.
Right now, I think the two main things Joannie needs to do to improve her World ranking are:
(a) Consistently skate clean SPs.
(b) Put at least one triple-triple back in her program (something Joannie said she hadn't been practicing this year because she didn't want to get injured, but she realizes she will need one next year, and she plans to start working on it again)
Joannie
did do both of these things consistently while training with Sébastien and the other coach, so I hope, regardless of whether she changes coaches or not, she'll be able to do them again!