If AC went up along with attack, HP best be kept low or fights are going to last forever.
And you know he is right at least if applied with all the magic items.
The thing is though in any edition of D&D everyone has a magic defense or three just to keep AC at a certain point vs. monsters.Heck early editions had enough magic items to keep the PC leveling up, use some of them up , selling some for training costs and to pass some of them down to henchmen (which is what was supposed to be done with the extras BTW)
This excess of items IMO detracts from the game.
It gets worse with 3x where game balance assumes that you have X amount of 6 categories at Y level and Z amount of disposables. That is flat out yuck. At least the old "hand me down" method felt like an ancient gift economy. The 3x method reminded me of video games and thats not a good thing.
Now later d20 games (the excellent Iron Heroes) had systems to allow for less magic items but this was in no way handled to any careful balanced degree for normal play. Even my own rules are pretty ad-hoc.
By the time 4e was starting to mature its DMG 2 (and later its Dark Sun) had systems were created to allow low magic games and inherent bonuses so that magic items could be cool and not just kit.
What I'd like to see is something like this applied to Old School games.
To do this a person would need to figure out how many pluses a typical PC has a a typical level to AC and to hit, give enough so that AC and To Hit ratios are about the same and than allow magic items to cancel out.
This would put fights on the same scale while allowing items to be special and a bit more magical as vs "just another +1 sword"