Flurry of Steel

[weaw]

About activates "controlling".
The good point to observe it is the way to watch the best Wars fights. While You're War (half-defensive, there is no BG-point today to build a pure tank), You need to switch attack/defense.
It's hard. Really. Because the best builds use one-row-strategy, or something like that -- the game will punish for "random" switch to second [,third etc] strategy row. It may punish even for "correct" switches...
So, let's look at the Wars. They have one offensive skill -- Death From Above, and one (the best) defensive -- Create Distance. You need then switch between Tank/Parry or Parry/"Bash" in order to allow a good work of these skills.

The Slayers strategies are extremaly "hard". Because they has no choice: You need a hard hit or You will die.
(Your sentence about "... to many activated abilities ..." is only half of diagnosis: Slayers hasn't an effective defensives at all! Slayer must be offensive, more even than Rages. Slayer will die whithout First Strike, for example -- i think).

So, let's think. You need [really] few offensives while You're a Slayer and You wish reach that Flurry. This is impossible...

Sometimes its possible to use some skill's rank to control the activates usage frequency. For example, my Eirikr has only 2 points in the Signature Movies and only 3 in the Feint. It's enought, at least it enought to have exactly what i need.
But You can't use this method on 5th tiers skill. Especially for Slayers. Because You'll lose ability to move in the other Sadows&Myst skills.

Good Slayer today ("today", -- the word for You, Dainoji) and if a good Slayer exists -- exactly hybrid.

[Just J]

In my opinion, the only way to build a slayer is hybrid/shadow with the 3 passive shadow skills. As discussed, flurry of steel sucks, and I also tried the other one for heavy armor usage. This also sucks, because advantage of a slayer is the speed of attacks, and you could only get 1 or 2 pieces of heavy armor anyway before going over 50% encumbrance. Disarm and sweep are hardly reliable, and if you avoid weak spot to take first strike, you can get only 3 activeated off skills: eviscerate, blood bath and vital strike, all of which have pretty nice effects. Snivler exotics or blades make the best slayers because of the bleed bonus. Even if fight only lasted few rounds, if you get blood bath in first round that's 500+ bleed dmg per round.
I never tried 2H slayer because you want to get the most attacks in as possible to try and get blood bath going. So a speed build is necessary for this, and, as weaw says, there are no def. skills available. Anyway, it's working for me as I was 26-29 in only my first full bg season. Not great, but not awful either.

[weaw]

But that's what makes Wars so fun to play with ...

No doubts!

In my opinion, the only way to build a slayer is hybrid/rage with the 3 passive rage skills.

It's impossible because of different schools. Or i'm wrong?

By the way. Shadow&Myst school has a strange architecture which makes hard to use it for hybrids: we need take at least one offensive acivate to deep into Slayer's or Trixter's branch.
For comparison, all the branches of the Arms&Armour school contains very useful passives in 1st tier which can be used by any build, almost any...
There is the opinion that Grim Determination is the best skill in the game, for example. It's hard to say something like that about Sweep or about Shank...
// Note also, the Grim Determination is not something "overpowered", but just very good and unique...

[Tyrst]

Not only are top slayers of necessity hybrids, but in all reality they are incredibly one dimensional slayer/shadow hybrids like Just J and Weaw said. Sure, someone could do a slayer/trixter hybrid...but to what avail? A manager would have to go through at least 3 activated skills on the trixter tree to gain access to an activated defensive skill, thus furthering the "too many activated offensive skills" problem.

I'm no slayer expert (or game expert for that matter, this is my first ever post), but slayers are extremely limited, and flurry of steel at this point deserves consideration as one of the worst tier 5 skills in the game. As many others have pointed out...the game is under constant development and Nate is constantly tweaking things (as evidenced by shadow dance now being a viable fight strategy for shadow glads), but I'm not confident that diversifying slayer glads from the hybrid builds they currently seem to be pigeon-holed into will be an easy task at all.

The Shadow and Mist school definitely does not allow for the same level of gladiator customization as Arms and Armour, but I'm sure that eventually someone will come along and figure out a killer new trixter build....maybe.