I would swap out Lotus Fan for volcanic rune and even put it on the second skills swap. NB's don't have an AoE immobilize, but knocking some of your mobs into the air is pretty effective. I've been playing a pretty identical build to this since release but definitely found volcanic rune useful.
Ransack - Reduces target armor, increases my armor and taunts.
(Switchable depending upon fight.)
Comment : If you go full heavy becomes redundant since it will overcharge and there are other more powerful skills that do the same and way better like Immovable object (heavy armor skill) it gives 1000 spell resistance and 1000 armor, even if the armor is capped on overcharge you will benefit from the spell resist and Knock Back and Down immunity (Take that crystal shard spams).
Another reason is because Pierce Armor grants minus 40% spell resist on target so both magicka based skills and stam based skill benefits from the it's use. That's why is way superior than Inner Fire.
Absorb Magic - Absorbs spell projectile healing for 115% of the damage, increases block mitigation and reduces block cost. I love mage mobs!
Comment : It's a meh skill really. You need to recast for every spell someone casts on you, way inferior than Dragon Knight Reflective Scales or Templar Eclipse, even so the heals is minimal.
Refreshing Path - Allows me to move around mobs with high mobility, DoTs, and HoTs.
Comment: You aready have Lotus Fan for mobility, the heals are minor, same with the DoTs, i use more on pvp for fast escape or chasing enemies until Shield charge/Lotus Fan is in range. The same goes for healing, the Siphoning attacks grants 4% of health back, making it kinda useless. Even more that you may trading it for a skill that will increase your survival odds.
Lotus Fan - Distance closer and AoE snare for those fights where the boss likes to teleport all over. A magicka ability, this allows me to reserve stamina for blocking and taunting.
Comment : Great skill if you want to save stamina! Aoe Slow on mobs and a quick way to move to the boss, a bit too expensive if spammed, but siphoning is there for it.
Swallow Soul - DoT, HoT, and increases all healing I receive. As a tank, this last is very beneficial.
Comment : swallow is not a DoT is a direct damage plus a HoT and a minor one. Its 25% per 2 seconds of the original damage up to 10 seconds. Means you do 300 dmg with it, you will heal 5 times 25% that value, meaning you will heal 125% of the original damage, also is not that effective with siphoning on. The good thing it's that you can cast it multiple times on different enemies, the effect adds up, but on VR dungeons minimal self heals almost useless due the brutality of the mobs.
Degeneration - Yet another DoT and HoT, Degeneration has the added benefit of healing me for striking the enemy with my weapon—something I am doing already.
Comment: Same reason. The Hot is your damage, that is way more useful for high burst damage builds that use a lot of hits and weapon damage, such as Dual wield, on tanking is 15% chance to proc to heal a low amount of health because siphoning strikes will eat up 22% of your damage, so 15% chance to heal a small value, is not that good for a tank.
Siphoning Attacks - While Leeching Strikes had the added benefit of returning health on weapon attacks, Siphoning Attacks' increased focus on resource return allows me to keep up the other skills as well as ensuring I have the stamina for blocking, dodging, and interrupting (you know—a tank's job).
Comment : PERFECT!
Ultimate - Veil of Blades - An AoE ability that not only reduces the damage I take but also that of my group, with the benefit of a Slip Away synergy that keeps the bosses who randomly drop or are immune to taunts from focusing on my group instead of me.