Myrrh, Frankincense, and Steel: Kurald Galain's Guide to the Magus

[Kurald Galain]

Small error in the guide, Celestial Armor is light, not medium.

Good catch.

Longarm increases my offense by less than Enlarge Person,

Longarm gives you another full round of attacks (since it works in spell combat); whereas Enlarge basically gives you +1 to damage while reducing your AC by two, negating some cover, and making you visibly a threat. Both allow you an opportunity attack against enemies that approach you (which you can use to trip them, too).

still pulls in more aggro than I can eat in a Round; I say this from the experience of having used it with this Character (see the "generally" qualifier). Shield will make me even less likely to be approached as a threat by the enemy

So, wait, you're telling me that your enemies always have enough spellcraft to know exactly what you're doing, and enough intelligence to counter it? And always have such good defenses that the party can only hit them 35% of the time? Because it sounds to me that either the GM is consistently throwing encounters well above your challenge rate, or your party needs to coordinate better and flank, drop crowd control, use a wand of Bless, and so forth.