I think this sounds great, and I would love an FE game like this!
I do want to point out a few of the disagreements I have though, because I'm too lazy to write my own post on what I want.
Firstly, I think that if third tier promotions were present, the level cap should be raised a bit above the usual 40, maybe to 50?
With the crits and proc skills being combined, while I do think that sounds like a neat idea, I think the effect of the proc skill should be reduced to make up for the additional x3 damage. Say, having Sol do x3 damage and heal 25% instead of 50%.
My last disagreement is on the visuals, while going back to sprites does sound nice, I would love to see what Fire Emblem could look like with high-res 3D models.