I think you're vastly overestimating developers willingness to design specifically around high SSD speeds when there is next to no benefit compared to traditional design.
Id say it's the opposite.
They would no longer be forced to design games around the limitations of an HDD. Is it a controversial idea that a developer wouldn't want to waste time creating extra unnecessary corridors, or navigating the player through streets in a specific manner so that the walls and buildings block out views in the distance?
It's easier for them to just design the games closer to the way they actually want, and it saves them precious dev time.
You will always have a fast experience with an SSD no matter if the game was designed for it or not.
Right, but like you mentioned, there are a lot of other bottlenecks aside from the speed of the drive.
That's why even if you use an SSD that's 10x faster than the HDD in PS4, you'll only get about 2x the loading speed.
Many of those bottlenecks are addressed in accordance to the SSD in PS5 to actually allow game loads and streaming to be 100x faster.
And for a game designed to work on HDD, there will still be a loading screen masked as something else. While in a game designed only for a fast SSD, the would be no need for them.
Hell, you don't even need SSDs at all for fast loading times. All you need is enough RAM and a predictive loader.
Exactly. For a typical PS4 game, the system memory has to already contain all the information you may need in the next 30 seconds or so of gameplay. This means that a lot of data you actually didn't end up needing takes up space just sitting there when something else could have been loaded instead.
That's why the PS5's SSD essentially being able to function as additional fast RAM in the way it does is so important. Not just the speed of the drive.
And the XSX's SSD will function in a similar manner from what I've read.
Maybe you can name a specific use case where it is needed to specifically code with SSDs in mind to get a significant speed boost.
Well, when I said faster SSD, I was taking into account the other hardware components being designed around it to make it function more optimally.
To eliminate masked loading screens in level design, the game has to be designed for a fast SSD (or something equivalent). But for let's say a quicker respawn load screen after you die, having other hardware components designed to accommodate the SSD is more important than the game designed for SSD. Although not having to repeat the same data hundreds of times in a cluttery and bloated game file could help the SSD to find the data quicker as well, but I imagine the benefits there are more minuscule in comparison.