To me, Cross Impact is totally broken. As I've written on a Rogue thread already, I've created a Thief this weekend and it became a master level rogue by the end of that day. The only skill that I maxed was Cross Impact. It was a sure one-shot against most enemies and it was the lamest leveling experience I ever had,
And that overwhelming power even early in the game (lower levels) is totally different to the other skills mentioned like Fireball or Battle Tactics.
Both Shadow Strike and Cross Impact can be used normally outside of hide. Just to show you the pre-ML situation in more detail:
Lvl 5 - Cross Impact: 700% damage; 8sec CD; +1 CP
Lvl 5 - Shadow Strike: 415% damage; 20sec CD; +3 CP; 15% chance that the next Shadow Explosion is considered to be made out of hide.
Lvl 5 - Shadow Explosion: 550% damage; 20sec CD; 5 CP required; optional 1100% damage
and to add another skill:
Lvl 5 - Grimtooth: 415% damage, 30sec CD, 10 targets, +10 CP, 20% heal; but no bonus from hide
So it should be obvious that Cross Impact actually does almost twice at much damage with half the cooldown.
Yeah, it's been a while since I leveled, and both my rogue and my sin are both Master Level, so I was comparing them ML-wise, but what you state it's true, pre-master-level Cross Impact actually outdoes both Shadow Strike and Shadow Explosion in terms of DPS. What I think as a solution would be a skill expansion post-master-level but I'll comment that later since you covered it too.
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First of all, I can't really stand the 'sitting ducks' statement. It's less than a 1sec immobility. Gush, it's not a 3sec stun, nor a a 15sec perma-stun... and sometimes you just want to end on the same spot anyways. So just show me a vid where this actually made a difference in PvP!
Eh, I have no idea how to do that (video) but I'll look it up and try to post it, still, I believe this falls a lot into the personal experience realm since as a Sin, when I PVP I usually try to cross trough my opponents and hit them on every pass, so when I do that with Cross Impact I feel the immobility, specially against casting classes.
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Cross Impact also beats any other assassin skill skill-point wise. Sure, by leveling Shadow Strike or Shadow Explosion to level 10, they might eventually turn the tides, but it's still possible to max all of them (even forgoing to max. Double Attack). Given enough Vigor, it's possible to rotate between these skills. Then, it might not matter that much whether I do a...
Cross Impact (out of hide) + Shadow Strike + Shadow Explosion
... or a...
Shadow Strike (out of hide) + Cross Impact + Shadow Explosion
... combo (assuming a CT trigger). Both have their advantages.
Therefore, the question isn't whether Cross Impact ends up better than or up to par to Shadow Strike (or Shadow Explosion), but whetther or not another high-damaging skill isn't just lame and simply too much, further rendering other skills / skillbuilds useless.
Considering that Assassins actually have the simplest skill rotation on the game and never had much variety (except for those sins that for reasons unknown took Hiding Exceed) even pre-AoV , I gladly welcomed this new skill into my usual 3 skill mashing rotation.
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That's why I made a few quick alternatives and asked f.e. what you would level, if Cross Impact would be a 250% damage skill that could cause the Mark of Shadow debuff instead... or what you would do, if Cross Impact would also restore 2% of your HP per level instead? Etc, etc.
Because right now, it's all too easy to level these three skills, starting with Cross Impact early.
That's interesting, I think Sins as a whole don't have much variety because they can have everything they need easily, pre-AoV there was slightly more variety where sins could choose between going max-dps or having a little more survival by maxing shadow armor, or the weird farming sins with hiding exceed. With AoV, the CD reduction on SS and SE rendered DB useless (and PW too), and with 20 extra skill points it was easily to max your DPS and still max your life saver even with the skill extensions, and even added a very strong heal on top of that (albeit "strong" on PVE, on a 1vs1 situation didn't make much difference).
Now, that heal has been balanced, making it virtually the same on a PVE or PVP environment, it's damage boosted and even added a slow on top of that, a slow, I'd like to note, on the fastest (albeit melee) class on the game.
I wouldn't touch the Mark of Shadow debuff, since it would break the sinergy of SS and SE, but I'd like to question why there are so many effects on a single skill (Grimtooth; AoE Damage, Slow, Heal, and Combo Generation) while CI get's only damage, I think what would force sins to add more variety would be taking some of these effects and divide them between Cross Impact (also expanding Cross Impact so it wouldn't be so broken pre-master-level), and make them scale, so if you want the best slow, and the best heal, you'd have to spend 20 points into Cross Impact and Grimtooth, instead of having the best heal and slow you can at the expense of 1 point.
The issue with that would be that Cross Impact is still a Thief skill, so any changes to it would affect Rogues too, and they already have a heal and a slow, that's maybe why we see so many skill effects on Grimtooth. Maybe it could get a new debuff like a dodge or defense reduction, or better yet, a dodge increase.
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Comparing these skills with Moonlight dance is a bit odd, because the rogue has several different skills to start with. F.e. this skill has a 20sec cooldown and there isn't a 580% rogue skill that generates 3 CPs like Shadow Strike. The rogue doesn't have a stun attack usuable without combo points and isn't exceptionally fast either.
Another note: Maybe I am doing something wrong here, but I can't use Moonlight Dance out of hide!
Agree with the first part, was my point between comparing Shadow Explosion and Cross Impact. On the Shadow Strike note, Rogues have (a now improved) combo mastery, that has great synergy with smoke bomb, that's the secret to moonlight dance out of hide.
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However, beside all the Cross Impact comments here, the changes made to Grimtooth, Shadow Claw and Ymir Form seem to be totally ignored.
Grimtooth f.e. could be another 580%+ skill, but the new 30sec cooldown rendered the skill almost useless, especially since most effects (CP point generation, slow effect, heal) don't get better with additional levels.
Commented on that above.
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Ymir alone creates an amor penetration of ~9% and with Shadow Claw it's 13%. Adding in additional armor penetration via cards & titles, and you might achieve 15% and more. That's a HUGE bonus. Reducing the defense rate from 75% to 60% f.e. results in a 60% damage increase. (That's the effect of a BT with 500 INT and 30% crit. chance). And there is not a single comment about that?
I always thought that Ymir on Normans was kind of... Meh, besides the instant heal, it didn't seem like a must have skill, considering that Noels on the other hand get a special effect with their Awake and even an extra, very powerful skill, that could also be used pre-master-level. So with this new change on Thief Ymir I think devs are gonna start making Ymir's more specialized, like, damage reduction, or dodge/parry on Swordsman Ymir, or more critical on Magician's Ymir, for example, so now it will feel like a must get, sort of trump card skill. I always wondered why Beastmaster's Ymir had an extra skill attached to it, maybe that's the way they're gonna go about it (in classes like Acolyte or Archers where Monks and Priests or Rangers and Beastmasters vastly differ).
Well, well.... balance might still take a while.
a possibility of one-shot kill is always there 
nerfing the penetration from Shadow Claw is not advisable also, for sure many Sins will rage comment about this 
the game is ady good for PvE (4/5) and for PvP it is (3/5). But anyway, you guys should also consider low-lvl thief class players when they are leveling; To devs : they should do the class balancing on the remaining classes (if possible, they should also balance and/or include PvP damage formulas); then it is the best time to judge if Cross Impact should be nerfed or not
