Some quick suggestions

[Honest-Red]

Just a few things I wrote down in passing;

I think over all Alteil takes for granted what it is. There is no reason why older generations of cards shouldn't be and aren't updated more frequently for SPELLING at least, and can we get WORKING scrollbars on the advances search window on the file editor and on the card text screens. Maybe it's just me being ****, but WHY should I go the extra mile to memorize card text if the game management can't take the extra time to add scrolling to their text windows on their flash game? Pet peeve; sorry I promise the rest will have a little more substance.

Note #1 - About Class
Subtype 1 could be named Factions instead of the vaguely confusing name it has now. Also it would be interesting if it was limited to 0-2. Units could benefit from being 2 Factions or they could be one faction OR the other depending on what you have in play/on the field. This would emphasize the drama of some of the action in Lavato.
-You could also consider working in a mechanic that lets Mercenary Nation units benefits from other Faction buffs. It makes sense; since they're mercenaries; if they were hired into a military they would receive their support during campaigns.
Eliminate Subtype 2 and all it adds to the vague, confusing classification system. Instead you should keep the system you do now accept call them "Archetypes" don't limit them and treat them like you do [Traits]
ex: [Arch] Warrior, Knight, Dragon Knight

At the very least try to reorganize the subtype system into something with some usefulness and consistency. Try to eliminate as much redundancy as possible. For example in this game, a shrine knight is one classification, that has walls separating it from others, but is it not also a knight? aren't knights in at their core warriors? Do you see how this might encourage variation in file construction?

Note #2 - About Trait/Skills
As more and more new sets come out, the cards from old sets will become more in need of general modification. I know this is was just done in Errata but hear me out; I feel that trait/skills of the older cards need general buffing.
Not just for Monsters but for them in particular some addition of [Trait] attacks as opposed to [Skills] would be a logical benefit.

Sea Claw [Trait] "Evolved Pinpoint" When this unit executes an attack action; you may choose the in range target.
[Trait] "Evolved Flight" When this unit executes an attack actions; do [Dmg=Att] to any random enemy.
[Arch] "Acolyte" or [Trait] "Critical Hit" When this unit executes an attack action; Target one enemy in range, then if that enemy is hit by this attack action subtract [Att] directly from that unit.

Common physical abilities should logically be less risky Sp wise, also to widen the gap of Sp cost thus making it easier to balance skills and add new expansions without balance complications.
ex: 1Sp [Skill/Rank-up] Slash - Do [Dmg=Att] to a random enemy row in range, if this unit has [Rank-Up] and less than 2 enemies are hit, you get another +1 Sp at the beginning of next turn.

Abilities that require discipline or sorcery should be the skills that cost/risk more SP than physical abilities but physical abilities cannot be without their limitations. Letting them return SP the turn after a failed risk would really help.
Finally I would suggest making ALL grim skills count as grimores. Instead of adding all the extra text though; just add a keyword or symbol for the skill name. I suggest a fancy looking "(G)" symbol. This would require maybe nerfing some grim count abilities to accommodate higher values but would make sense and could be a the first of similar mechanics.
Here are a few other skill ideas I had;
As an alternative to free revival staple cards; temporary revival fee units.
[Trait] You get +1 Sp after this unit revives during [Set Phase: Revive]

1Sp [Open] Rush - Set this unit in an open area of your field.
1Sp [Start] Preparation - [Conditional/Did not use "Rush"] This unit gets...

[NitroDino]

If Sea Claw gets that trait he will be nerfed because without the action skill you can't hit Feline Kin Fighter or Manta Ray. Stupid suggestion.

[Honest-Red]

If Sea Claw gets that trait he will be nerfed because without the action skill you can't hit Feline Kin Fighter or Manta Ray. Stupid suggestion.

No offense but I think you missed the point entirely. The suggestion wasn't about any card in particular. It was a suggestion for deeper organization. I was looking for real constructive feedback. But for the sake of discussion; it's less of a nerf or a buff and more of a change effect definition. But excluding it from being able to hit 2 units that, require high sphere investments and which can't be hit by MANY units is not really that big of a deal. If the only thing putting Seaclaw over for you is it's ability to hit those 2 units in those 2 situations than I'd say those 2 cards are too game breaking but they aren't. Also by that logic, any unit with low attack is stupid because there are units with Defense, and Soul Skills are stupid because a couple Lawtia cards are immune to Soul Skills. I know what Giant Manta's effect does, and it was intended to not be able to hit Manta, Teleport/Sorcerers, Magic Sealed units, etc.

My point was exactly - that Monster units, with natural evolved skills should have [Trait] attack actions as apposed to traditional skill attacks. But this was just one part of a bigger suggestion to change the usefulness of Sp.

[Icyglare]

At the very least try to reorganize the subtype system into something with some usefulness and consistency. Try to eliminate as much redundancy as possible. For example in this game, a shrine knight is one classification, that has walls separating it from others, but is it not also a knight? aren't knights in at their core warriors? Do you see how this might encourage variation in file construction?

I also want to reclassify men and women. They are two separate genders but saying women makes it sound like it's a type of man, it's confusing. Which leads into the subject of changing the word human, back in 1973 I....

*ramble*
*ramble*
*ramble*

... and animals don't wage war on each other, so who's the animal now?