32GB is the limit imposed by the Secure Digital High Capacity (SDHC) specification, not FAT32.
FAT32 supports 2TB drives, with a standard 512 byte sector (or 16TB with 4.096 byte sectors) which is (coincidentally?) the same as the latest Secure Digital eXtended Capacity (SDXC) specification, so FAT32 should be viable for some time to come.
The biggest restriction with a FAT32 formatted drive is the per file size restriction. Since FAT32 uses 32bit file pointers, which means that no single file can be larger than 4GB (actually 232-1). Most of the time this isn't a problem, but if you want to transport movies or virtual machines which aren't split into multiple smaller files, then this might cause you problems.
As an aside, in an answer like this, I can't help but illustrate it with a favorite picture of mine which compares 8 bytes of magnetic core memory from 1953 with 8GB (8 thousand million bytes) of flash from 2008:
In the same space as those 8 bytes from 1953 you could now fit 8x or 12x 32GB uSD cards (when you take into account thickness too) so who knows where we will be in another 55 years? Probably wondering how we got by with only a couple of terabytes in our phone. *8')