I don't see how, because the typical enemy does not have 500/500 Physical and Magical armor, but more like 350 P / 650 M.
Abstract enemy have only mega-pants with 350 p /650 m. (Dont u forget that this values is on ur gear?) U are striking with a sword. With every 100 dmg hit his pants loosing 100 total armor - and ofc its 35 p and 65 m. U can not shread with ur hits (for exemple) only magical protecting patrs of the pants
Your system is realistic, logical but almost same like having 1 type of armor. Second is unnessesary
P.S. Even if u split weapon dmg in some unlogical values like 10%/90%, in mid- and lategame it will be enough to shred all at the same time cos of OP dmg. Some Assasin with Highground jump in final fight - backstubbing 15000+ vs 1500/8000 and 9000 hp. and the enemy is ready to all types of cc. Or another partymember with 80%/20% weapon could do the same vs 8000/2000.
it is not good that 1 party member coold shread both enemy resists at the same time.
But if dont split weapon dmg in your system and make weapons possible to hit armors simultaneously (like in pants exemle) but add new ingame stats like physical and magical resist it will be unable to shread both armors at the same time