>what would be ideal language for system programming
There's nothing wrong with a language like C or even C itself, you'd just have to do little changes to make it less niggerlicious and stop compiler vendors from adding special snowflake changes that makes everything complicated (by making the base language good so they're not tempted to). You could even bridge more of the gap between a "systems" programming language and a general programming language while you're at it by designing it smartly.
Operating systems for sure should be completely redone. Every single one of them. The API should be minimal and sensibly designed. The OS should give you low level access to things like networking without slow and niggerlicious socket systems. It doesn't need to be like Linux where every part has to be a replaceable piece, it just needs to be well made and flexible and let you customize or replace parts afterwards. It SHOULD however be FOSS, since it'll probably eventually succumb to cancer just like everything else, so being FOSS will allow people to take it a new direction without losing compatibility with 95% of all software.
Mobile OSes should be just minimalistic desktop OSes with a different UI, not these shitty locked down cancer towns that give you neither control nor transparency and require a shitty bloated language to program for.
Graphics libraries need to be rebooted as well. OpenGL is shit, Vulkan is shit. I don't want convoluted cancer that even your own documentation doesn't explain properly, I don't want your shitty snowflake OOP api, just give me something as minimal and straightforward as possible.
I don't know enough about hardware to say anything about how to improve them, but GPUs for sure should be more transparent. I think part of the reason graphics libraries are shit is because the GPU is a box of secrets that we don't have access to very deeply.
I've heard something about letting programs live in their own space so they basically bypass the OS or something, if that's viable then that sounds neat. You could probably do interesting things with the web too if that's the case.
I'm not too familiar with how the internet works, but when I looked into TCP/IP it seemed pretty shitty. It looks like one of those messed up machines that grew beyond it's design, just like everything else about the web. Just reboot the whole thing and design it from the ground up to the purpose that we now know we need.
I'm not one of those people who obsessively want to remove scriptability from the web because it'll just inevitably return anyway, possibly in some shitty cancerous way again because the web wasn't designed for it and then someone shoehorned it in. That's why the web should be designed to be scriptable, and offer as much interactibility as possible without scripts, and let you disable it. It shouldn't be able to do anything on it's own if you disable scripts, but it should be able to do various things when you click buttons and shit.