There's many, many things open to interpretation in D&D. I think that if you get too caught up in details of alignment you're using it wrong. It's just a general idea of outlook, it's not prescriptive of every action a person will ever take.Things that are often up to interpretation, and therein less-than-helpful.
In any case, I think alignment is fine as is. The description could be tweaked I suppose, and I see no reason go have "good and evil" in spells that are impact aberration, celestial, elemental, fey, fiend, or undead because there's not really a correlation
If you don't find it useful, that's fine. I just find it tells me something different than TBIF. When it comes to monsters and TBIF I don't want to read that much detail most of the time, it would be pretty useless for sorting and filtering, I think they are just as open (if not more so) to interpretation than alignment.