I've main war since 2.0 launch and even tested it a bit in beta and going into 4.0 puts us in a weird situation. Onslaught I agree is quite niche for the cost it requires. Upheaval is a decent off-gcd for the same cost as Onslaught. Shake it off is nice to have, especially in PvP, though content design will determine its utility. Inner Release looks like a great ability on paper and the amount of immunity it provides is really good and the trait for Infuriate cd reduction is only a good thing. However, you can't Infuriate outside of battles, we lost bloodbath, brutal swing and even though you can block and parry from behind in 4.0 why does Raw Intuition still crit from behind.
I only really have issues with two skills but here's a couple of options to improve their viability among other QoL things.
Defiance/Deliverance
-Costs 25 beast gauge. 10 second recast.
Berserk
- Additionally restores 20% of damage dealt as hp. Duration and recast unchanged.
- Increase Berserk to 40% increase in Attack Power. Duration and recast unchanged. (Highly controversial but just throwing it out there)
- Increase direct critical hit rate by 10%. Duration and recast unchanged.
Storm's Path, Storm's Eye, Butcher's Block
- All give 20 Beast gauge. Storm's Path heals for 100% of damage dealt. (much needed imo)
Infuriate trait
- Inner Beast, Steel Cyclone, Fell Cleave, Decimate, Onslaught, Upheaval reduces Infuriate recast timer by 5 seconds upon using the action/skill. (Much needed QoL)
Onslaught
1. Give Onslaught a stun, duration 3 seconds. 20 Gauge.
2. Increase potency to 200. 20 Gauge..
3. Reduce cost to 10 Beast gauge. Potency and cd unchanged.
Upheaval
1. Give Upheaval a stun. Gauge is unchanged.
2. Upheaval gains a 100% Direct Critical Hit at 100% hp. Gauge is unchanged. (I would love this)
3. Upheaval puts a DoT for 18 seconds. Potency 20. Potency unchanged.
4. Gain "Hungry Beast" buff. 20% of damage dealt is converted into HP. 10 seconds. Gauge and potency is unchanged.
Atm WAR's theme is of this "reckless abandon, angry berserk tank" but some of the skills hold that back with the high cost of beast gauge. I'm still excited for war in 4.0 but it still needs a few more touch ups, specifically stance switching costs, increasing all combo finishers to 20 gauge, Infuriate trait fix and the viability of Onslaught in PvE. Also I'm sure the OP hasn't seen any of the tool tips but WAR still is the only tank with a Slashing debuff.
MTQ Tool Tip video
4.0 Embargo Skill changes