I base this proposal on countless of hours of orvr and scenarios trying out a multitude of builds and gear equipments.
The issues:
1. [Fierceness]: this ability has a increase of 40 weaponskill at the loss of 40 initiative. It stacks up to three times, once for each ability used after the buff has been cast. It buffs/debuffs your entire group.
More often than not you find yourself in a group where the initiative loss of this ability is not worthwhile the ws, and you make your team take more crits which is not very great, especially for a slayer who is already extremely vaulnerable to crits. This is a 1 min CD and has a duration of 10 seconds.
2. [Even the odds]: This buffs the users toughness by 35ish for each enemy within 30 feet up until 6 enemies. Again 1 min CD and duration of 10 sec. This buff is great, it works both as an "oh sh*t" ability when you get bogged down and also strong buff for when you push into enemy lines and expect to take a lot of flak/focus. But for being a core defensive ability, it doesn't do much against casters as a dwarf or order rdps against choppas.
See the core abilities in the trollslayer and skavenslayer tree here
http://www.ror.builders/career/slayer
Proposal:
Buff [Fierceness] with 1% crit for each stack totaling at 3 crit.
Buff [Even the odds] with a bonus 7% disrupt and choppas "mirror" ability buffs 7% dodge.
(EDIT: Greenskins get dodge and dwarfs get disrupt, makes more sense because in lore slayers are strong against magic and choppas, well they're obviously fast and agile + I realized getting both was kind of OP)
Benefits:
[Fierceness] This will give this ability more use for the group, regardless if you could use the ws or not, making up for the loss of initiative. More appropriate risk/reward.
[Even the odds] giving this ability a bigger impact on your defence versus ranged making this ability much more useful and making slayer more viable in orvr creating more "windows" of combat where you can do your role on the frontlines.
Conclusion:
As many other careers your survivability is closely linked to your damage output and your offensive skills. For example shatter limbs require you to hit 9 targets to apply the debuff efficiently(and buys you time by prolonging their rotations), no escape can aoe snare, and rune of absorbtion requires you be in melee range to hit an appropraite target to survive. Slayer/choppa provide great offensive survivability for themselves and their wb, but their core abilities should to be enchanced for their roles to shine.
Spoiler:
Edit2: I changed my mind on mirroring the buffs so I changed it to something i think is much cooler
