Given this stuff is almost certainly going to be TLC, if not 4 bits-per-cell, and on a very small process node, it's going to be in the sub-2000 range at a guess. Combine with a low capacity, and you are going to have a few people wiping it out. Especially if it's used as a cache drive.
I have felt since the invention of non-mechanical large storage media that any form factor that lets people plug single chips or arrays of these devices straight unto their motherboards make the most sense. If they solder these directly to the MB then I would suggest that they have expansion boards much like traditional PC memory that can be easily added or removed with arrays of these chips. I predict that you will be hard pressed to distinguish your RAM from your SDD not long from now.
I agree with Wardwing, If mobo manufactures added a built in SSD then they could have a hole other performance branch of boards. This also could cater to the lower levels too, it would give those on a budget that have a HDD already, an upgrade to an easy SSD/HDD setup. Toss the 64 GB drive on the board just for the OS and away you go.
QuoteAlso, phones/tablets generally don't have SATA controllers. They use something called
eMMC.This would need whole new SoCs to be built."
Many popular arm SoCs have integrated sata controllers such as Samsung Exynos and Nvidia tegra 3.