The upside is that in the block you're expected to accept /48s,
nobody will have a /32. The downside is that anyone who gets
a larger-than-minimum sized allocation/assignment can
deaggregate down to that level.
I don't think ARIN is planning on giving out more less a /48 but
more than a /32- at least that was the impression I got. End sites
get a /48- ISP's get a /32 or larger- and that's it (I could certainly
be wrong). As such, deaggragation in the /48 block should not
be an issue because no one will have more than a /48 in the
first place.