Hi Rockingly,
From what I understand the onboard devices not working is not intentional. It just so happens that we get lucky sometimes and they work on certain versions / hardware configs. Now, removal of NIC drivers that is intentional and when it's to stabilize the stack for production I totally agree with that. We always have the option of running the older versions (which will run happily for years) or just use PCIe add-in cards.
IMHO, nobody cares more and supports their lab rats more than VMware. With that said, it's important to speak your voice and VMware does in fact listen. Anyway, keep your head up stick with us. There are always creative ways to keep using ESXi with the same hardware at no additional cost (i.e. take one box and set up OpenFiler or ZFS for your storage and USB boot the hosts).