But the same things happen every time you move up a difficulty. The only notable difference between Gold and Plat is that you're not just shooting one faction any more. Everything else is just scaled up accordingly.
True, but the enemy composition is the big thing that matters most. Instead of four different factions you now have four quite similar factions, which don't make any sense thematically and have no guiding principles in their designs. And there's just too much boss spam, which requires you to focus way too much on armor DPS.
With health & shield gate mechanics I'm referring to player's gates, which in Platinum last only for 0.01 seconds. It's not just scaled up (or down, in this case). It means that you can be taken from shields to death in one frame - by a hunter. Combined with endless amounts of staggering, this forces constant RHA abuse and makes the game incredibly lag dependant.
Of course, all this has been discussed to death. My point still stands: Platinum isn't just harder Gold, it's different. And you know I'm not alone in thinking this way.