From what I understand, Jim Lefebvre knows hitting. He loves to talk hitting and he loves to teach hitting. The Padres however weren't hitting and it may not be because he doesn't know how to teach hitting. It's just that he may not know how to teach hitting to the Padres.
Say for instance you take a college professor who knows how to teach, but then you stick him in a classroom with special needs kids. He won't be able to succeed, because, while he knows how to teach. he doesn't know how to teach kids that are special. Padres hitters are special needs kids. He may be trying to teach them hitting theory and they are busy eating glue. The Padres need someone that can dumb it down for them. See the ball, hit the ball type stuff.
As for Jake Peavy, he wasn't doing the Padres any good. One starting pitcher, no matter how well he pitches, is not going to help this terrible team. This is a case where quantity over quality is a good thing. The Padres rotation is a mess and if some or all of these four new Padres can contribute in the near future we have a better chance of turning this club around. As great as Peavy was at times, he could only pitch once every 5 days.
We were lucky enough to see Peavy in his prime, he got his Cy Young here, he contributed to some winning albeit frustrating seasons and now he moves on. The Padres wanted him to leave, he wanted to leave and so everybody is happy, except for some of his fans.