Hi,
USB disks in the storage pool are already a difficulty on their own - splitting those more up by a hub adds to potential causes of trouble. In the past users have experienced issues like disks not longer recognized as members of the storage pool,
which could have been caused by the specifics of the enclosure, cable quality etc. Also with an increasing amount of cabling the risk of an accident caused by a human is increasing (pulled cable, falling down disk stack ...), and do not forget, that the bandwidth
of USB 2.0 is shared between all these attached drives.
I don't know, what you have for a home server (OEM or self built), but you could try to exchange the internal disks for larger ones one by one or get a new case with more chances to attach internal drives.
Best greetings from Germany
Olaf