Alignment based encounter and event tables are something I really like as an idea, if you have certain alignments in your party or have been a big nuisance to aligned entities then you’ll be finding your enemies sending their forces to mess with you, or the side that likes you might drop a little something nice your way.
I also think it would be nice if alignment got you something, just out of the gate for being that alignment, a specific spell or feat or resistance or proficiency or a familiar option or something:
‘you are Chaotic, you can pick [appropriate number] of the following features:
You can cast charm person PB/LR times,
You are proficient with hand crossbows,
Add PBd4 damage whenever you deal psychic damage,
You have resistance to lightning damage
Ect, ect, ect...’
Staying loyal to an alignment would gain you more boons, if you swapped maybe loose one temporarily and have to repick the others from your new alignment’s options, if you were repeatedly changing alignment it’d cause you to loose all your boons.