Overall I would would like to see a buff to Leap and Rend, and a small change to Whirlwirnd. I know I suggested them before, but for me they would really enhance the gameplay.
Leap
Leap could have 2 charges by default instead of a cooldown, which would give the skill a lot more flexibility, so it both can be used to leap into a group of enemies, but that you also could eventually use the second charge of Leap as a means to escape.
Currently you can only use Leap either as a tool for engagement or as a defensive tool for escaping (I am talking about the base skill here, not the version with Lut Socks and the MotE Barbarian), but a second charge would give the base skill a bit more flexibility, which would make the skill more appealing because it would give additional utility and maneuverability, while still not making it OP.
The Launch rune or the Toppling Impact rune could get redesigned to give a 3rd charge since they are not useful in the endgame and the Lut Socks legendary boots can be redesigned to grant this new rune for free and maybe also to increase the damage of Leap by xxx% or reduce the cooldown of Leap by xx%.
This tweak to Leap wouldn’t change much for MotE Barbarians since the gameplay would stay the same, because you still could Leap 3 times in a row and get the charges back quickly by spending Fury via Seismic Slam, but Leap would become more attractive during leveling and for other endgame builds as well if it would have 2 or 3 charges by default or via runes.
Giving Leap a second/third charge is better than Lut Socks’ current 2 second window in which you can leap 3 times in a row, because with charges you could choose when to use the charges, instead of being limited into a 2 second window, which gives Leap more flexibility.
Rend
Rend would be more interesting for non-Wrath of the Waste builds, if it would incorporate the effect of the Mutilate rune into the base effect of this skill, which is that enemies take xx% more damage from either all sources or your own attacks (but multiplicative, not additive) while they are under the effect of Rend. A 10% or a 15% damage increase from all sources or from your attacks should be enough.
It would give other builds an incentive to also use Rend as a secondary damage dealing skill in addition to their main damage dealing skill, because skills like Hammer of the Ancients, Whirlwind, Seismic Slam etc would also (indirectly) get buffed by it.
The Mutilate rune then can keep its current effect, but simply increases the amount of additional damage enemies take while under the effect of Rend further, so this wouldn’t require much tweaking.
If more stuff is required to make Rend more appealing to players, its base duration can be increased from 5 seconds to somewhere around 7-8 seconds while still keeping the same damage per second.
Whirlwind
I always thought that Whirlwind needs a rune that increases its AoE (from ~10 yards or whatever it currently is, to ~15-20 yards). The Hurricane rune is a perfect fit for such a rune, especially since its current effect is mostly underwhelming.
The damage increase of Volcanic Eruption is okay, but it could kinda use a bit of flavor, like leaving behind a trail of fire for x seconds as well.
The Dust Devil rune was buffed many patches ago from 120% damage to 180% damage to better work in alignment with the Wrath of the Wastes set, however, this also leads to the Dust Devils rune outshining all other runes. Maybe some readjustments can take place here by nerfing Dust Devils but buffing the Dust Devils damage bonus on the Wrath of the Wastes set, to bring the rune back into line and to provide more choice for LoD builds and during leveling.