My reasoning isn’t quite the same as yours, but I use a few Artha hacks too.
Personally I find Deeds points to be kind of underwhelming, considering how rare they are and in contrast to Call-Ons which can function like a free ‘virtual deeds point’ every session. (I.e. call-ons work like saving grace, but for a specific ability, and it doesn’t contribute towards a long-term epiphany, once per session).
My hacks are as follows:
Saving Grace no longer acts as a mere call-on does. Instead, it simply will makes the test succeed—but you won’t get to mark advancement, and there’s no marginal successes. Basically, it’s for those “I don’t care about marking the test, I just wish I had passed that”. The Deeds point still contributes towards an epiphany.
Epiphanies for Skills only require 2 Deeds points to permanently shade-shift, not 3 like stats and attributes—you still need 10 persona and 20 fate though. This rule actually harkens all the way back to Burning Wheel Classic. I’m not really sure why they changed it the revisions.
I’m also debating adding an artha power that lets you add +1-3 Ob to static tests by spending Persona, like for social test at Ob = Will, where you can’t actually actively resist like you would in a vs. test.
I’ve also started emphasising the use of focus in my games. Did you know there’s an Artha power called Focus? I sure didn’t for the first two years I ran this game! I’m 99% sure that it’s there so that you can get an advantage die, and have it contribute to the test difficulty, to get more routine tests if you need them. It lets you work Carefully (+1D) and then you can spend a Persona if you fail the test, to nullify the additional failure consequence imposed by working carefully. Basically it’s a really circuitous way to get a normal advantage die out of a Persona point instead of the usual artha die (which doesn’t contribute towards the difficulty).
To address the issue you raised a bit more directly though (and I do this too), is that, if you want to see more epiphanies just hand out more Deeds. If you want a higher powered game, lower the bar for getting a deeds a little bit. I think my games see a deeds point given out at least once every 20 sessions, but usually more often than that.
I handed out a deeds just this week actually, for one of my players who saved a village from a corrupted werewolf sorceress. Just some random forgettable village, but he risked life and limb to save them, so I gave out a deeds.
Edit: And yes the other thing you can do is just shade-shift an ability during a trait vote, or perhaps by going on a special quest. Though I’ve not actually done this in any of my games before.