TRIGGER ALERT: HARMONIC NERDSPEAK
I got this book on jazz keyboard voicings, and it has you do everything in fourths instead of thirds. It does have an open, Mcoy Tyner-type sound when you play like that, but a maj7 chords turns into a 6/9. The problem is that the 7 is the tone you really want. The author makes fun of voicing using 3rds, calling them "third city" and other derogatory nicknames. He has you play the 5th, which I rarely do, and suggests that the same combination of notes can be two different chords, depending on how it is interpreted. Granted, I don't usually play harmony with both hands in the first place, because I need to play the melody too.
I'm sure I'll get something out of this book if I persist. Fourths sound cool and "open." Nevertheless, as a comprehensive guide to keyboard voicing it leaves much to be desired. It never puts these in the context of an actual song. In the internet era, this kind of presentation of the material, with no audio aids, seems a bit dated.