I'm on The Greatest Dog's side on this one, your cards need quite some balancing.
Let's start with Komachi and compare her to a similar character: Suika.
Character | Suika | Komachi |
Passive | +1 Range, +1 Attack/ Turn = 1 Powerup | +1 Range/ Damage, +1 Distance/ Damage (thus, with 1 Damage about as good as Suika's passive, with 2+ damage way better than her) + Card draw for defeating enemies + bigger hand size |
Spell Card | Change everyone's distance to 1-5 | Change 1 player's distance to 1 for everybody |
Differences in Powerlevel: Passive Abilities:Even without +card draw and +handsize, Komachi would easily be better than Suika. But with it, she's just a clear powercreep of the highest caliber.
Differences in Powerlevel: Spell Cards:While Suika has to decide whether everybody should be out of range for her (or her teammates) to get a breather, or to put herself in danger and reduce even her own distance to a low number, Komachi simply says "Yo, everyone, kill this one person for me. Kthxbye!" Without putting herself in danger and still getting rid of the person she wants. And even if nobody else is attacking her desired target, at least Komachi has an easy time hitting this person now. And usually, you're just picking fights with one person at a time anyways, so this ability is simply better than Suika's most of the time.
(I'm not even taking synergy into account here, as both Suika and Komachi have great synergy between Passive and Spell Card.)
I think the table shows quite well why your Komachi needs quite some reworking.
After all, all characters should be about equal in this game. Yes, some are a bit more powerful than others (Yuyuko), that's unavoidable, but not to this degree.
As for Kaguya V1, it's funny how you first said something about combating game length, and then list Kaguya who evidently lengthens the game extremely with options to cancel attacks (thus saving hit points thus keeping the game go longer) and the ability to play cards during other people's turns, which, due to interrupting the game flow, also makes the game take longer.
Kaguya version 2, however, is also too strong.
Let's compare her to TWO different characters.
Character | Patchouli | Aya | Kaguya |
Passive | +max handsize | cancel Danmaku cards by discarding Danmaku cards | + 2 cards + cycle cards twice per turn cancel attacks targeting her by discarding one item in play |
Spell Card | + 2 cards | + 0 - 5 Danmaku cards (base chance per Danmaku card is something like 25% or so.) | Attack a player 0 - x additional times. |
Differences in Powerlevel: Passive Abilities:Yes, Kaguya's cancel effect is less flexible than Aya's (btw, yours can still cancel Spell cards the way it is worded), but in addition to her other passive that (almost) freely generates two cards, which is an ability that is so powerful Patchouli (and Aya, too, to some extend) has it as a
Spell Card, and additionally lets her cycle, she just has WAY too much power.
Differences in Powerlevel: Spell Cards:Like I stated above, what Aya And Patchouli need their Spell Cards for, Kaguya can simply do in her passive. And instead, Kaguya additionally gets an ability that is just a straight up better form of Master Spark. True, Kaguya does not have the same item synergy that Marisa has, but instead, Marisa needs Powerups, Kaguya can use any item, so it's about equal again. But then Kaguya attacks multiple times instead of just once, each attack requiring a new Dodge card to evade, meaning you deal a lot more damage to a single target than Marisa on average.
So yeah, Kaguya is basically 2 - 2.5 characters in terms of power, even this new version.
As for the whole "superior to Master Spark" thing, bear in mind that it also has the same weakness as Master Spark in one respect: Items. Seal Away and Borrow can slow her down, and repeated Danmaku shots can reduce her offense even if she uses her defensive passive, as the sacrifice of an Item is a fairly hefty price to pay to cancel an attack.
That still makes it simply a better Master Spark. And Master Spark is not bad to begin with, even without Marisa's synergy.
As for Kaguya's passive standing in conflict with her Spell Card (her having to discard items to cancel an attack), in the worst case scenario, Kaguya does not make use of PART of her passive ability. But a) she still has the choice to use it and b) that does not change the fact that Kaguya's Master Spark + is better than regular Master Spark.
The Range / Distance defense measure is to keep people from instantly murdering Komachi in one go, and serves as a way to become more dangerous the lower your health is.
If people deem a character dangerous enough to want to destroy them in one go, that does not mean that you need to give them a defense mechanism, but to make them weaker so that other players do not feel threatened by them. Or leave them be and actually let the players kill them quickly. While it's not fun for a first time player, it's a risk to consider for more experienced players (not saying I'm okay with Yuyuko's current power level because of that, I'm just saying that you should not be making them even more powerful for the sake of new players.)
Also, to be at +3 Distance / Range means that you are effectively at one health most of the time, so the Komachi player has a little breathing room at that point, but not a lot.
+2 +2 is goo enough in my book already, IMO.
And with a Focus equipped, that puts her to +2 +4, which is kind of ridiculous.
And there are a lot of things that can hurt Komachi at that point:
Hijiri after using her spell card or when countering Komachi's attack with her passive.
Sakuya's and Meiling's spell cards, provided Komachi tries to attack.
Last Word and Yuuka's spell card, since neither of them care about range.
Tenshi's spell card, provided she has more Danmaku cards than Komachi.
Suika's spell card can negate the distance buff outright.
Youmu's Spell card makes everyone in range for her, so distance means nothing to her.
Cirno has a +2 Range passive, so she only needs a single Power to reach Komachi(2 Power if Komachi's max health is 5 due to her role).
That requires that at least one of these characters has been chosen by a player and the players of these characters do not believe to be on the same side as Komachi.
And while it is true that some characters can hard counter another, that does not mean that it is okay to create characters with this knowledge in mind. Every character should have about the same power, no matter if there are a select few characters that can counter you. Because, after all, there are characters who can counter the named ones as well, e.g. Tenshi can be countered by Patchouli due to get greater hand size, or Komachi, who... ehm... has a greater hand size and gets card draw for killing people, meaning there's a good chance she actually has more Danmaku cards in hand than Tenshi, if her player is smart.
What I mean in the end is, even if you are at 1 or 2 HP left, there's still a lot of ways for you to survive, and Komachi's passive is busted.
All that, in addition to what you said can hurt Komachi at that point, and suddenly that Distance isn't a good a defense as one would of thought.
The thing with distance is, though, that it is a big part of this game's mechanic, and the fact that there are quite a few Spell Cards and regular cards that ignore it is a little alarming to begin with.
As it stands, you should still operate with the though that, on average, each player only has one Powerup, and thus only a range of 2 (which is the only reason Focus is useful to begin with).
Thus, the fact that there are exceptions to the rule of Distance should NOT be taken for granted when designing cards for this game.