A new class is mainly based on whats fitting/cool for a new expansion.
Demon hunter is probably the most fitting for a burning legion expansion. Its also a community favourite that has been asked for years. The tinkerer is probably my second favourite. It fits warcraft and it has huge potential I think.
---------- Post added 2013-05-11 at 07:29 AM ----------
My take would be that Spirit/Hit conversion will be removed as it leads to a sub-par itemization - spirit items are less valuable and hybrid casters can use all int items while pures have no interest in spirit. Iirc GC even said he himself dislikes that conversion. Expertise might go away too.
Blizz also should stop adding dps/tank/healer hybrid classes - those don't promote healing and tanking roles to people really, just add new specs to play as for players who only like these roles. I think it's best to add a pure dps class with various dps types - archer/caster/melee - that type of thing.
While not imperative, the addition of a class capable of using mail, int plate or ranged weapon is good for game's itemization. What can be done is adding a petless caster-archer hybrid that's using int mail or int and agi mail in different specs. Meanwhile a way to convert armor can be introduced for this new class and Holy paladins. They could permanently convert agi bows/xbows/guns into int weapons and str plate into int plate.
As for a new class, the best addition would be caster-archer hybrid in my opinion. Lots of melees have already been introduced with new classes and not a single caster/ranged dps. Also the only archer-type class utilizing ranged weapons is a hunter, To be unique the new class can combine these two playstyles - have some non-instant spells and instant magic-imbued shots. Petless to distance from hunters, using mainly Arcane and Shadow magic school as there's currently no such combination and Arcane is used only by 1 spec of 1 class.
If not a Dark Ranger/Demon Hunter type class, I'd vote for a Battlemage - one spec melee-ranged hybrid, another - ranged. The mere idea of some kind of Blinkstrike ability seems really cool!
Tinker on the other hand is a type of class I'd like to avoid. I highly dislike technology-based characters in a fantasy setting. We already have gnomes, goblins and engineering to fill this niche, that's enough for me.
Superficially they will be similar to Hunters, but that's it.
That said, as I mentioned before I doubt we will see new classes anytime soon. The game is quite "crowded" already.
Dark Rangers will overlap with Hunters.
Demon Hunters will overlap with Warlocks - although this situation is of Blizzard's own making; when they gave signature DH abilities to Warlocks for no reason.
Tinkerers will overlap with the Engineering profession.
Alchemist will overlap with the Alchemy profession.
IMHO Warlocks overlapping so much with Mages is the source of their problems. Mages are very well defined in the fantasy genre, so Blizzard can't make overly drastic changes to the class. This leaves Warlocks with whatever gimmicks Blizzard can think up. However that didn't work out very well, so Blizzard back-peddled to the wizard-archetype in order to keep the class viable, resulting in Warlocks ended up a lot like Mages and lacking a unique identity.
---------- Post added 2013-05-11 at 11:41 AM ----------
On second thought, there might be a way to "add" all of these classes that players want and fix a few problems with the game in the process.
Just merge Dark Rangers with Hunters as a spec.
Warlock -> Mage spec
Demon Hunter -> Rogue spec (or just outright replace the Rogue class with Demon Hunters incorperating popular aspects of the Rogue class)
I highly doubt they're going to give the Metamorphosis system to another class, at which point you don't even have a Demon Hunter. I also doubt they're going to suddenly strip a Demonology Warlock's identity from them.
I would like a Int mail-wearing Pilot class, you just get the 6 vehicle buttons, but as a pilot you can adjust what vehicles can do (your personal one, and the vehicles you use in quests/raids)
you can adjust your controls to be either melee or ranged, and to be in accord with your gear (like if you've got a lot of crit you can use abilities that like crit over haste) or to fill in gaps (if you have tonnes of parry, click this button for a dodge buff on a short cooldown)
Dps spec: Shredder
Tank spec: Steam Tank
Heal spec: some kind of fix-it-bot? like pet based healing maybe.
Ewok Sith Lords are all about Agility
Come to think of it, if we were really following patterns.. Wouldn't the next class be implemented in the next-next expansion? New classes skipped a generation in the past.
And, if you think about, there have been class developments in every expansion. BC gave us alliance shaman and horde paladins. Wrath was DKs, and cata added a whole lot more race/class combos. Not getting something new for classes might break that pattern (that blizzard is not beholden to).
Before MoP i'd say the possibility of having a DH was high but now not so much. A Demon Hunter class would've needed a evasion/blink tank which is more or less filled by Brew Masters with their stagger (misdirection) mechanic. Plus with how Demo has the Glyph of Demon Hunting, I really doubt that DH will be a possibility.
What do they need, is a int plate dps class. Spellbreaker, arcane warrior, and perhaps a soul healer.
---------- Post added 2013-05-11 at 09:49 PM ----------