TLDR: I tried it, it was complicated.

"Detect" spells would instead give you basically, mental whispers of good or bad deeds the target had done (non specific, just stuff like "thief, murderer" etc...). With the worse the deed the louder the "whisper".

Spells that only affected people based on alignment were a lot more fluid, gaining minor buffs or penalties instead of simply not working.

It was a lot of work on my end, I mean, is Grog the Goblin really evil? He was raised in a cave, the only life he ever knew was raiding human villages, and humans in turn raiding his village. He wasn't taught morals or ethics, just "kill or be killed". He never went out of his way to be particularly cruel to anyone, but he's certainly killed a couple of kids (hey a 3' tall human is almost taller than Grog!).

But Grog is fighting the party for what, 1 minute? Was it really worth to effort to determine if he was truly an evil person or not?