So, random off-topic thought. We know there are some people who choose to make Praxis their main magic system. However, the Praxis spells Hunger's been offered so far don't really lend themselves to being someone's mainstay. Refinement of Quickness and Artful Thorn both have high costs in a kind of "Existential Stamina," which prior to getting Tears of Winter (Adorie) made them un-spamable. Imagine trying to fight an army with Artful Thorn as your main combat spell - it wouldn't work, you'd tire yourself out before running out of enemies. Refinement of Battle is the only thing we've seen that is applicable in a wide variety of situations, and that's an EFB equivalent.
I think, therefore, that Hunger's Praxis spells are not representative of what a Praxis-specialist would use. Artful Thorn works very well as a boss killer, and Hunger has his other magic systems for dealing with anything else. Refinements of Place and Quickness were both clearly intended to address Hunger's lack of utility effects, specifically mobility. What Hunger was offered is not the stuff that a typical Praxis user would start with, but techniques that did things he couldn't do already.
I imagine a Praxis Main would probably use spells that were weaker, but had a lower stamina cost - or they would make use of several passive effects similar to Refinement of Battle but less... powerful/expensive (most practitioners are not going to be pulling out 25 Arete stuff when they start out). Alternatively, perhaps there are Praxis effects that fortify the user's self so that they can use more Praxis spells before being tired out, and until the practitioner gets one of those online their Praxis use is severely limited. It is supposed to be hard mode after all.
On another note, I'm thinking that the Accursed probably has some lesser remittances, artifact or ability, along the lines of Adorie's Bloodline that get handed out to Cursebearers that take Imperial Praxis as their primary.