A lot of the major riffs that play the upper part of the chord can be heavy on the doubled thirds, root tones and embellishment etc, which makes them unrealistic with a non- chord/scale tone in the bass. Having the bass note in a chord like BMaj/C also play in the piano part would help to make the chord sound better. This is mostly a modern jazz/latin style issue where there are lots of signature phrases covering every chord type.

Best regards

Alan