The problem with major active use of the secret ingredient is that nearly all of the abilities are passive, or build upon something else. The +Spellcaster level and +CLs, the main abilities of the class, all augement another class, be it wizard, sorcerer, warlock, suel arcanamach, or sublime chord. The spells you get from those classes are gonna overshadow pretty much everything in the build because they are SPELLS.

The other abilities, besides the slam, are all passive. +Str and +NA are things that is hard to really showcase other than a note, same with the immunities. The slam attack, IMO, is one of the coolest features given that very few classes give you free natural attacks, and almost nobody made reference to having it or using it.

Its not a showcase class. Its has almost no active abilities of its own that bring it to the forefront in a build. If you emphasis its spellcasting, well, spellcasting is WAY better gotten from any other class. If you emphasis its resistances and immunties, you get most of them from the +0 LA Warforged class. There just isn't any good way to glorify something that can be gotten through other means, and we were all marked down a lot for it so far...