They absolutely are powerful sub-systems. I am not saying they aren't but to my mind they are too power.
In my play experience, NPC's gain Style Points pretty quickly. Also, in my experience, when PC's have won duels and Mass Murders, they have done so with Blessings. I like the even playing field of the Aspects for everyone. It is one less thing to memorize.
With the maneuvers, it doesn't gibe in my brain-meats how you have this system with wagers, where you can gain a spoonfull of narrative control but then you've got these bits on your character sheet telling you how you can swing your sword. I am all for creative constraints but it doesn't fit with how dueling has worked at the tables I have played at.
My first instinct is to use these as straight-up Aspects. I'd rather model a character's devotion to the Suaven through their creation of shrines and their relationship to the Suaven itself, as in their interaction with them and their priesthood. If the character wants to show their devotion through the system, they can gain more aspects reflecting that suaven, and build shrines via season actions.
So that would grant the character a three dice bonus on duels and/or mass murder, give their opponent a two dice tag to use said maneuver against him, and compel a character to martial prowess?
Same goes for blessings. A character could gain a three dice bonus on risks related to the suaven s/he worships, an opponent could get a two dice from tagging the aspect and compel the character to behave in accordance with his/her believe?
That really is not how Aspects have shaken out at my table. It is not a straight up 3 for me, 2 for you affair. Aspects can only be tagged if the character knows they are there or has used a special power to gain their knowledge. I like that knowing your foe gives you dice; that works for me but it is a rare fight where every aspect dice exchange is 3 for me and 2 for you. There is a matter of context and the knowing.
The main reason I'm tinkering with this house-rule, is because Blooded is terrifically dense already. These two things are great but in the context of the greater whole, they feel like the fat that can easily be trimmed.
But we'll see, see what my players think of it and see how it works at the table.