Re: well
First of all, Katja deserves some slack. Last season she rode Superstock (on a Gixxer750 like you Rob!) and not Supersports. She ended up 6th. in the championship, with a high runner of 2nd. at Misano. True, she was a member of the richest (read most powerful) team in the paddock and there were rumours of some very unstock components on her stock Gixxer, but she can ride a bike fast. She is now at GPs because Dorna bought her to steal one of SBKs major assets. She'll get some mid-field placings later in the season and more consistently so next year. World Champion? Nah!
Walker is at GPs for same reason. Only European country where SBK is really popular is UK, so Dorna needed a British rider to spite SBK. They do a lot of matchmaking. Don't worry, it works both ways, hence Juan Borja on a Infostrada Ducati at the cost of Ben Bostrom last season, to get a few paying visitors to the race at Valencia (didn't work, the place was seriously empty).
The politics of sport.... Thank God there is still some good racing.