I've been playing 0.2.7 for 35 hours or more in the last week. I wanted to share my thoughts and some suggestions (please delete if unwelcome)

Soul Enchanter
In your showcase video, you described this as a "side-grade" to the vanilla enchanting table, but it's actually far better, imo. If you have a mob spawner farm (which is an essential thing to have in survival) you will have no shortage of crystals. The leveling curve makes levels 1-5 come very quickly, so you could easily get a fully-enchanted item much earlier (notwithstanding Eidolon's own progression system), and for much less cost than the vanilla enchanter.

There is nothing wrong with that default if that is someone's playstyle. My suggestion is just to add more config options to give ops the ability to make the Soul enchanter cost more XP, cost more crystals, restrict which enchantments appear on the table, or even set a "minimum" XP level to use it.

Apothecary Brewing
I found myself not bothering with this brewer. The difficulty of finding blaze powder usually falls off immediately because blazes only come from spawners. Having to pull potions off of the new brew stand just to add the modifiers is just a hassle (because of Mojang's design, not yours).

My suggestion for this is to add some other kind of drawback for side-grade purposes. For example you could make potions take twice as long to brew. It removes the need to have both, and the annoying item swap.

Also, I prefer your brewer's design to Mojang's but they kind of look redundant sitting next to each other. I would love it if your mod just let me "upgrade" my vanilla brewer to yours via the magic crafting table.

Rituals
It might be useful to have a subtle particle effect connecting a stone hand to a brazier when there are items placed inside. This would show the player they have valid placement, and confirm which have paired if they have multiple braziers for some reason.

Additions?

• Soul crystal blocks with that pink color palette would be beautiful!
• What if witches were not hostile if you are wearing the wizard cloth set?
  -- What if you could toss them soul crystals in exchange for alchemy ingredients (exactly how Piglin trading works, essentially)
• Enchanted gold candle wall sconces
  -- perhaps consider renaming the candle to "Votive Candle" or something more descriptive. Many vanilla+ mods (quark for example) have different versions candles, and it can be confusing for modpacks.

Everything I didn't comment on is phenomenal! keep up the good work!

Re: soul enchanter.

I'm not a fan of configs, but a rebalance of this feature is planned at some point. It's probably a bit too powerful at the moment, though as you said I primarily blame the exponential nature of XP (in packs with Allurement, I suspect this is less of a problem). And actually, partially because of mods like Allurement, just increasing the experience cost or soul shard cost isn't the right route IMO - it doesn't make the feature less powerful, just more time consuming. I have some more sophisticated ideas instead of that, but I can't invest too much time in the mod right now.

Re: apothecary stand.

I don't actually consider this a side-grade, I think of it as a means for getting potions before going to the nether. Things like curing zombie villagers are gated behind potions, and potion effects can be fairly useful - but by the time you're geared up enough to handle the nether, most of the time potions are no longer valuable. The apothecary stand is mostly just there as a stopgap to address an aspect of vanilla progression I find weird. So, I don't plan on giving it the full modifier functionality, and I fully intended it to become redundant so I don't really see that as a problem.

Re: multiple braziers.

I'd rather just improve the means by which braziers select nearby objects. Braziers are intentionally very simplistic, to support arbitrary setups - as long as the right item is available in the right radius, there's basically no additional "right" or "wrong" setup rules to follow. So, I don't see a huge reason to carefully outline placement rules as Botania does. Braziers don't "pair" to hands like you mentioned, they just search an area around them for a compatible item - the only point of confusion I can think of is that a ritual might pick an item from a place you didn't expect it. Since there's no maintenance cost or anything I feel like this is a pretty minor inconvenience. But perhaps it could be addressed by simply making braziers search for nearer item providers first.

Reopening with enhancement tag for your suggested features at the end.