This is unlikely to be an actual issue, but I found this funny.
Necromancer's Quickened Casting appears to be missing a very important set of words: once per day. Thus, there is absolutely nothing stopping you casting it before every spell, say...Create Thrall, creating infinite thralls/taking infinite attacks on any poor soul within 30 feet.
It does say "minimum of 1" in Quickened Casting though, so quickening Create Thrall does nothing.