I have taken issue with the rituals for Terracotta Soldiers and Enliven Statues, for roughly the same reason: 8% chance to destroy the terrain.

First, the rituals are economically decent. Both cost no resources and 2 actions, resulting in 3 summons every 2 turns.

The units are also not bad, the Terracotta Soldier is a respectable pikeman and decently sturdy, compared to human troops and specially your (economically viable) summons. The statue is actually great, outclassing even armors in offense and defense, at once again 0 iron, at the cost of being a tier 2 ritual (which is not actually a big deal for the enchanter) and slow (which is).

And by my accounts you will summon 13 of each before destroying the tile. The statues would compete with the Juggernaut for the temple or it's base value of 1 gold which is not a big deal, but I don't think 13 terracotta soldiers are worth a clay golem.

And the statue slowness would not be a big deal for any other summoner class, you could easily make a cheap summon every turn with the free action, but not the enchanter. Not only every summon is local sensitive, not one is 1 action except armoring flesh golems.

I'll give this some thought and try to play enchanter again soon. I don't think the terrain destruction chance can be entirely removed with these summons still being free, but maybe the chance could just be reduced a bit so they're more viable.

Consider changing the dynamic of the ritual. Instead of 2 actions to summon a figure with the chance to destroy the terrain, make, say, 6 actions to summon a lot of figures with the guarantee to destroy the terrain. Maybe with some small iron cost for the Terracotta, to not get too rushy.

I think that's the winner. I like this because it would flip the use from being a "cast every turn" ritual for an apprentice with a "push your luck" element (that is currently overshadowed by more reliable animate weapons rituals), to a one cast that can be used in the field by your main enchanter for quick reinforcements at the cost of consuming a valuable terrain that could have been saved for a better quality summon later on.

Some notes:
Animate tools is terribly strong. It beats out other economy rituals on pretty much every metric but AP cost. Enchanters generally have high prices to contend with, but doubling all your mines (and then, because you can afford it now, everything else) is just nutso bonkers crazytown. Enchanters aren't known as OP, so I guess they need this?
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It kind of demands that you spam lesser mastery looking for it, and takes a lot of micro to use to its potential. I don't like those things. I'd really like to see it limited to one per tile... maybe buff it somehow.

In other news, gargoyles are bad. Sure, they are tanky little buggers. But they are melee troops that can guard 1:walled citadels, which can be guarded way more effectively by archers and 2:random temples why are you guarding this?

Ought to give em a stone throw attack so they aren't so bad at their jobs, and make them midrank so they stand on the walls, where a gargoyle belongs.

Honestly I think animate tools being limited to one per tile is fine without even buffing it. It will still be a fantastic "core" ritual but just without the potential to snowball into absurd incomes. I will definitely be doing a pass on gargoyles, a minor spoiler, they play a role in the upcoming class.

The T3 ritual that crafts a random item currently is the only thing that costs gems. This cost is mostly for show since you probably have enough mines at this point in the game to fire this spell on repeat without running out. The biggest cost to this ritual is losing the AP on your High Enchanter... with a smaller opportunity cost of not selling gems for gold (which is just a thematically weird and mechanically clunky perk to get from a ritual unlock.)

I could see the ritual having gem cost shifted onto gold, so that it actually has you choosing between it and something else.

I could also see it being fine as-is if other T3 kit gained a gem cost. The rituals that consume a library to teach a golem magic are quite nearly unpickable, IMO. I think they could lose the library requirement with a higher cost that includes gems.

I don't have strong feeling either way on this one so I'll give it some thought. I think I like the idea of adding gem cost to other t3 rituals the best.

Enchant Quill Rework: Limit to 1 per space. The dancing quills gain an enables recruitment trait that gets you extra chances to recruit human mages.

Currently this a level 2 ritual that, while cheap enough, gives a very small benefit. Disappointing to research and hard to justify spending precious enchanter AP on. This buff will give it a reason to exist that fits in with tier 2 army building. It also opens up some space outside golems to fill a mid-game army.

Now that enchanter has a clear connection with agartha, I propose the T3 rits for Iron, Silver, and Gold golems be buffed to allow the use of Agarthan Iron, Silver, and Gold deposits respectively.

These deposits are a smaller sacrifice to make than a surface mine, but IMO that's fine as a reward for getting enchanters to Agartha.

Gold is maybe the odd duck on this list, since this change would make it significantly easier to access gold golems and possible to get more than one, where it currently isn't. I'd say it's fine if you increased the ritual's cost--you could even make it more expensive on gold deposits and less on gold mines using a tile discount.

I think this is a good suggestion since the access to Agartha is not an amazing perk without some extra synergy with other features. I also had the initial reservations regarding the impact it could have on ease of metal golem creation, but it is also quite time consuming to actually get to these deposits so at least for now I don't think it's too big of a buff, and an increased cost for the underground deposits as you suggested is definitely an option.

One aspect of this is a bit "up in the air", I do intend to keep the Enchanter's built in Agartha access intact, but Prospectors may be migrating to Guildmaster as they are a natural fit for the Mining Guild. Still TBD, but worth noting that the means of accessing the underground ores may be changing a bit.