Originally Posted by
Yoshimiko
There are four primary points you should be looking if you're aiming for mythic 15 and on in your class.
1) AoE
Pretty simple, can your class do well at consistent 3-4 target cleave? Bonus points if you can control this AoE in case of panic CC. The big classes here are: Combat rogue, Fire mage, Frost DK, MM Hunter, WW Monk. After that, some second string AoE DPS are Enh shaman, Fury Warrior, Arcane Mage, Demo lock. These classes may be able to keep up with the best at AoE/4 target cleave, however they all bring some downside. When reaching into the high mythic+, Ele Shammies become very very potent due to how their AoE works and the constant 3 targets to chain lightning.
2) Single Target
Again, a basic numbers game. Sometimes you have to burn a boss, sometimes you have to burn some trash - being able to burst for roughly 60 seconds is pretty important. Demo lock, Assassination rogue, Feral druid, Ret pally, Spriest, Fire mage are the top-dogs here. Bare in mind, Spriest will cost you roughly 3-5 seconds of time unless you're in halls(which she'll cost you ~3 seconds if she's night elf or between 3-9 seconds if not for every boss). *Don't look at SIMs for this. They assume a 5-8 minute fight. You need to assume a 1 - 2 minute fight*
3) CC
Incredibly important - way more than most people give it credit for. Being able lock down the entire pull is what makes mythic+ 13 and on possible. It's important to be reliable, as well - so something like Ret Pallies stun in Blackrook hold might be good, it's also not going to happen in a good chunk of runs. Locks, shammys, WW Monk, Spriest, hunters, warriors, Frost DK. *Bare in mind* Only bringing 2-3 specs with an AoE Stun is worth it due to Diminishing returns.
4) Utility
Utility is a few things, but in general can you cheese a mechanic, can you make fights easier and can you speed up the dungeon? This is hard to quantify, but a lot of people vastly underestimate Ret Pallies +~4% group DPS and overestimate shammy's Bloodlust. In the entirety of the dungeon, Lust will bring ~+2-4% DPS. Also, Earthquake is the most underrated spell in the game in Mythic+ - it alone makes Ele Shammy one of the top 3 specs in Mythic+. There's cheese on lots of boss and mechanics but one of the larger ones is in Blackrook hold:
Amalgam of souls. If everyone can immune/cloak/guarantee survive explosion you can ignore the adds entirely. Holy Paladins are the only healer who can do this, though. Ret Paladin, Rogue, Mage, Spriest(up to about Mythic+13) and Hunter can all cheese this mechanic. Prot Paladin, Prot warrior and Demon Hunter can cheese this as well. Blood DK can as well but...kinda needs a shitload of healing afterwards. This can save a dozen or so seconds at minimum. As you reach higher mythic+, this saves more and more time. This isn't the only mechanic you can cheese like this, either.
For general Mythic+ stuff, I'd consider Enh shaman to be the weakest of the three specs. Having an Elemental shaman makes every pull vastly easier due to how EQ works and they have some of the highest 3-4 target cleave.
If you want to make a pure Mythic+ character: Hunter is almost certainly top-dog. Beyond that, most high-end group is likely going to want an Elemental Shaman. It allows you to pull more, safer. Mage is always going to be very strong, either as Arcane or Fire. Demo lock is great at everything except mobility. As you reach into very high Mythic+ this becomes less of an issue and they really start to come in as very high dps, but lower Mythic+(read: +6 and lower) are going to fall woefully behind the 'better' dps.
Best of luck!