As with every gen the console manufacturers talk about their secret sauce and by the end of the gen it mostly accounts for nothing.
I wouldn't say that exactly - depends on the gen, and individual consoles in question.
I'd argue PS2 gen has done well for itself.
While PC was promising it - it was on the consoles that common-place (and sometimes heavy) usage of post-processing math actually became
practical first, several years early. The same console gen also pioneered programmable graphics pipelines, and hw-accelerated video/audio codecs that were useable for realtime assets. Much of this wouldn't come to PCs for years, and it was even longer before a mainstream PC would do all of it. Some specific accelerated paths (like the so very hyped
Mesh Shaders) would take full 2 decades later to arrive to PC consumer hardware.
And like it or not - all of that allowed all 3 consoles to punch about their weight, in their own ways.
Anyway - if there was 'least utilized' in terms of unique features it would have to be all the mid-gen consoles (NDS-i, PS4Pro, X1X) - they barely touched their special features due to a tiny target user-base and effectively being at the mercy of 1st parties to use any of it - 3rd parties as a rule just don't bother.
All joking aside, which of these secret sauces are actually going to deliver and which ones are just bullshit terms?
I think I/O stack has already shown its potential and it's just going to grow from there once software catches up. It'll possibly be close to tail-end of generation we start seeing that though.
Everything else listed was incremental tweaks - so you should expect incremental results from it. It certainly won't make consoles compete with 1000Watt bricks with 10x the compute throughput.