Ok, it doesn't bother me, but traditionally, Rangers have been a "no heavy armor but all the weapons" class (along with Barbarians). So there is a flavor reason to split weapon and armor proficiency apart that some would defend.
Plus some classes do have an eclectic mix of weapons for similar flavor reasons, like Rogues.
I'm not against the slaughter of sacred cows, but some would consider this a bridge too far.
I mostly like this, but I think the Strength requirements should be lower, especially for light armor. Many classes that get light armor are not incentivized to have Strength, like Rogues.
If this is about "Strength should matter", armor already has weight, and you need some Strength to carry it around. Making people have to have higher Strength to be able to use a class feature (armor proficiency) seems a bit odd.
Light Armor, no minimum Strength.
Medium Armor, Strength 11.
Heavy Armor, Strength 13.
Ah I see. While I prefer characters who are more well rounded and don't have "dump stats", I still wonder about forcing Dexterity-focused characters to invest in Strength, but I guess Str 12 isn't the worst thing that could happen.
I do disagree about "no one wants an odd score" though. A Nature Cleric might choose to have Str 15 so they can wear heavy armor effectively, yet have no real desire to make melee weapon attacks using Strength (say, by using shillelagh instead).