The limitation is that you've got all your class abilities built up towards doing this, And it's nothing but damage. Oh and a Barbarian or Archer will easily top this using multiple attacks that had less dice to them but an even higher static bonus to the damage. It actually TAKES insane-seeming dice multipliers like this to even make vital strike remotely viable without putting some mythic levels into it. Viable, that is; not actually even close to multiattacking, but meaning you're no longer total dead weight in battle.
You aren't replacing big bad guy over there with a completely devoted thrall. You aren't finding out everything the party will need to know about the evil noble's castle. You aren't calling down the gods themselves to aid you in your endeavors.
Aegis is one of the best martials you can be or have, so it does have a good amount of versatility to go with its damage. But all that just adds up to a solid, competent choice... not a campaign violator. Just looks really bad because so many other "equivalent options" are so ill-designed they can't even do their own role.
Soooo.... What are people's impressions of the Metaforge, Pyrokineticist, and the Cerebremancer?
Metaforge is 3 levels or forget it. Not all that needed now that there's Fighter's Blade to help compensate for your nonsoulblade levels, but dual summon could be handy and you might want just another 3 or 4 custom points without damaging your enhancement bonus (after all, if it can't keep up with a bought weapon...)
Pyrokineticist is kinda neat but overall quite 'meh'. How many things aren't highly resistant or immune to fire that you'll deal with?
Cerebremancer requires splitting into two casters. We know how much 'better' that is compared to actually maxing out your caster levels, though this does diminish the sting a bit. However, if you can get an equivalence (either magical or psionic; whichever you don't have) on the cheap combined with the +CL or +manifester multiclassing trait, it suddenly becomes quite awesome, as you get 10 caster levels then for cheap.
Basically all three are "optimize or there's really little point"