Yesterday i got some time to test my new skill Can't Hit Me! and it's damn powerful. But let me tell you more in detail about how i grind mobs: Before i got this, i was able to solo tank and take down approx. 5 mobs up to +4 levels of my own (ofc the lower the more), without any real danger to me. Everyone telling you Da'Toughest specced tanks can't solo mobs and are useless are wrong. The question is how you do it. If you take on one or two mobs after the other you'll take a longer time then some DPS specced player, as your DPS output is of course lower. You need to use your strengths, which is survivability! For me as a tank (with mainly toughness & wounds tank gear), it's no difference if its one or a few mobs banging my chest. So you need to calibrate your mob grinding in a way that you pick up just enough mobs you won't be in danger to die and that you're downtime is not increased. What i would do is, to gather up to five mobs... maybe use Challenge initially to gather them up nicely. Then i would use whatever skill rotation (for higher damage until now i used 'Ave Another One tactic) i see fit on a single mob of them while using Big Slash and Raze whenever available. The mobs would die one after the other but because i have a few on me (gather them nicely so they all get hit by cone attacks) i can make more use out of the multiple mob abilities. If you stack up on thorn potion like Brief Thorn Ointment this will speed up grinding multiple mobs even more. These potions are rather cheap and not hard to come by. Even for solo play i was able to keep up a very good pace and did not have the feeling others were plowing through the mobs while i was stuck banging on one.
Talking to some other classes, taking on five mobs higher level is already more then some can handle. Let's check on how Can't Hit Me! improves this... Using the above skills/potion i vary it a bit now: Gather all the mobs and maybe use some self-buff skills then switching to Can't Hit Me! when nearly at full Action Points (AP). While you channel the skill and your APs slowly drain all mobs hitting you will take damage. Depending on mitigation they will at least take 70-80 dmg if not more. Add the damage from the thorn potion to it and you have a nice and steady flow of damage on ALL mobs going. As soon as Raze is available, use it (because the cooldown needs some time to refresh). Then maybe use a few skills depending on the situation and go back to Can't Hit Me!. Rinse and repeat. You'll drain quite a lot of AP so you should use Get 'Em whenever it fits the rotation - this skill is best used when you're around 40%-50% AP as it will make sure you can get going. Using it when depleted of AP is not that good IMO. You can also use it before going into the channeling. With the above skill rotation I'm able to take down around 10 mobs at the same time with a good pace to it. Comparing that with other classes that's pretty good if you ask me. It should be noted that i use a shield with +block and also make use of the Good Wif Shield tactic. This gives me close to 100% block chance while channeling.
This will work best on melee mobs tho. If you face ranged/magic mobs it becomes a bit tricky to gather them. Should there only be a few just gather the melees on top of the ranged and you're good - of course the block damage will also affect ranged attackers standing away but with the current AI the mobs tend to run away when they're to low on health and if they run to far, they can reset and end up back to full health again. These scared mobs starting to flee are a bit borked if you ask me. Depending on the situation you might need to break of the channeling and kill the ones running away, should they not come back by themselves. Just use any other skill or the hotkey again to break off channeling.
As you realize, the above drains a lot of action points, a lot. I suggest you stock up on the +AP jewelry that you can get at rank 29. Each gives +3 AP regen and in addition i use the Grim Changehide that yields an additional +4 AP regen, so in total that gives me +16 AP regen and you can really feel the effect. Together with Get 'Em this keeps me going for a long time. Due to the AP regen I'm even able to solo hero mobs around three levels below me.
I did not really had the chance to test this in RvR yet, but while more situational i can see great potential when being focus fired and such. To close off this excursion, here is a bit about my experience while teaming up with others: I grouped with two guildies of mine (Zealot & Sorcerer) and we were doing PQs. I would run around and gather approx. 30 mobs and we would take them down *very quick*. We were owning the place and respawn could not be fast enough. I used the Menace tactic, run around and gather the mobs and we would just AoE them down. Important of course to let your group know you don't really generate any aggro while running around and gathering mobs, so they have to wait until you're stationary and had 2-3 secs to generate aggro to be safe. We went into Mount Gunbad yesterday night and i used a similar tactic to tank multiple mobs. The times when the Chosen would own you on multiple mob tanking are over. This really works like a breeze. Maybe I'll post more in detail about each wing of Mount Gunbad once we went back and cleared wing 3 again.
Addon Tip: Check out Mini World Map if you haven't yet. It will give you a small world map, which is very useful to find directions and also in those capture the flag scenarios to see where the flags are.