No, I do not think the sequential perform is "subpar" and its a problem. 1 real issues killed Optane, esp for consumer sector.Intel fumbled Optane so badly, it's a real shame.
They create this amazingly fast storage technology for random reads/writes, but then pair it with outdated first-gen controllers that have subpar sequential performance. When you're selling the most expensive SSD (by far), then it needs to excel in every category.
If you want people to combine an extra module with an HDD, then the pairing needs to be either good enough, cheap enough, or simple enough that people have a reason to buy it over a standard SSD.
Maybe they could have used optane's longevity to take advantage of people wasting money on Chia?
3D Xpoint also could have replaced the SLC cache for a high performance optane/flash hybrid SSDs using a single integrated controller. But instead they glued their slowest optane module to their slowest SSD and said "eh, performance, who needs it? ".
People want this tech, Intel. We have just been waiting for a good-enough product sold at a justifiable price.... With ryzen compatibility.