3e already had the armor mechanics pretty much nailed down with the Max Dexterity Bonus being different on every armor subtype rather than between the light/medium/heavy classes, plus having the Arcane Spell Failure chance that would get in the way of arcane spellcasters wearing heavier armor even if they were profiecient with it, and the penalties on Dexterity-based skills from heavier suits. Same with the different subtypes of shields.
5e dumbing the armor mechanics down is one of the many reasons I find it far less appealing, as there is indeed no logical reason behind picking some of the existing types of armor over the other. Hide armor's only saving grace is that it's the only piece of medium armor available to druids (apart from the non-metal rare magical ones), but padded armor is just plain useless, and so is ringmail (where the only use case I can think of is a Life/Nature cleric who for some reason dumped both strength and dexterity wearing it). Having Lae'zel start with the best kind of medium armor also throws the balance out the window in that regard (and I hope that in the full game they will downgrade her to a breastplate or something).
The one approach to counteract all that would be having interesting enchanted varieties of the gear that would normally be overlooked, but that introduces an even greater issue of being flooded in too many magical items than there already is now. Otherwise they will have to rewrite the armor rules, and considering how hostile people can be even to actually well-implemented and system-improving cases of Larian's homebrew stuff, I somehow doubt it'll go over well.
