I like Haseley b/c of the track record AND the eyeball test.
He's a pure hitter, one thing I don't like about a lot of hitters these days is the launch angle/pull crazy aspect of HR derby baseball. I predict as pitchers max out velocity and move back toward "pitching" (focusing more on command and a complete repertoire of pitches), the HR derby hitters will suffer. Haseley goes with the pitch, hits to the opposite field but has the pop to pull it into the stands.
You're seeing it with the new pitching coach, no more emphasis on high FBs, now it's more back to traditional pitching, move the ball around the strike zone and change speeds to keep hitters off-balance.
One thing I don't like about most of the Phillies' hitters is they pull too much, which means good pitchers can exploit that tendency - and if you're building a playoff team, you should focus on hitters who handle good pitching, not ones who feast on bad pitchers. Guys like Harper and Hoskins have enough power to go yard anywhere, and should just try and barrel balls. Guys like JT, Segura and Didi have "pull" HR power, but have more alley power and should limit the HR stroke to inside mistakes instead of trying to power everything.