- The shiradi random procs say that they have a chance to proc one per spell or once per arrow, but the actual code makes them have a chance to proc per time the spell does damage. You can get a lot of procs from spells that do damage multiple times, like chain missles and meteor swarm. A shiradi sorcerer can spam these spells and hope for helplessness and instakill procs, and doing thgat is easier and cheaper than landing DC-based spells.
- Many arcane damage spells have a fixed level cap so the 5 caster levels from draconic and magister, which would normally be their main selling point, don't do anything. A shiradi sorcerer casts cone of cold, does the same damage that a magister or DI would and has a chance of proccing random stuff.
Well-stated. Particularly the latter portion; even a Tier3 Shiradi first lifer is going to perform more efficiently than a Tier5 Magister or Draconic Incarnation simply because the two legitimate "arcane" destinies don't shore up caster deficiencies when they need to.