I have to say, I'm extremely impressed with the quality of this hack. I just finished Chapter 16 and having a blast so far, all the rebalancing done has made for a fresh and exiting experience while also adding some much needed challenge to FE8. There are a few small things I want to bring up though, a guess I'll start with the most important of my feedback, the difficulty. I am only on chapter 16 and playing Eirika route with random growths, so take this with a grain of salt, but I don't see the necessity in lowering the late game hard bonuses from +4 to +2. Nothing in the game so far has had stupid levels of stat inflation. The most noticeable for me was chapter 15, It was definitely a difficult spike, but nothing there was unmanageable. Narratively I think it fit very well, and gameplay wise it was very fun and rewarding to play. Unless the next 4 chapters are hellish, I would say don't alter the enemy stats. Vanilla Sacred Stones is a cake walk even on Hard, so I welcome a little more difficulty.
The other things I want to bring up are all animation based. For starters the enemy Griffin Riders in chapter 15 (and I assume in general) will always display their hit animation and sound effect even if they miss. Not really a big deal but though I'd bring it up none the less.
The next thing is more of a question really, but would it be possible to have Ephraim use Seigmund in his Master Lord animation? I know FE7 changes the Lords animation when they have their Legendary weapon equipped so I assume its doable, but I know nothing about FE ROM hacking so it may not be possible in FE8.
Last thing is just my personal preference, but can you change Eirika and Ephraim's great Lord Pallets back to vanilla? Ephraim new one is ehh for me, but Eirika's pallet just looks really off. Both of their alternate promotions look really good, but the Great Lord repallets seem unnecessary. I think this may be one of the few cases in this hack where I think the philosophy of if it ain't broke don't fix it applies.
Other than my small nitpicks, I really want to stress how good this hack is. Just playing through and discovering all the small adjustments to classes, weapons, enemy layouts, skills, and animations has been so cool to both play and experience. Seeing Joshua promote into a fully custom animated sword master, and Tana gaining staffs once promoting to Falcon Knight is just so fun to see. All the custom animations and sprite work added in really helps distinguish this from Vanilla. The small little changes is what really makes this hack for me, lots of things that didn't need to be changed, but were changed anyway. Not to mention that the gameplay experience is really solid, to the point where it feels official in it's polish and map design. The effort put in doesn't go unnoticed or unappreciated, and I can't stress that enough. Sacred Trilogy has replaced Sacred Stones for me, whenever I want to play FE8 I will definitely be playing this hack!