Hi guys, in case anyone is interested - here's the post about my thoughts on Demo Warlock flavour/gameplay. Mostly cosmetic and visual, not performance-improving or dampening. Would like to hear your thoughts on this one, thanks!

So, before Mists of Pandaria expansion shaked up Warlock class pretty significantly, I've only been playing one spec, and that is Affliction. I kinda liked to think of my Warlock as of some kind of a ranged DK (even before DKs were released), spreading disease and plague across the battlefield. Then, getting older, I became to think of my Warlock as of an actual Warlock, not a Necro/Plaguemancer and it came to me, that Affliction spreads not the... well, "physical" diseases DKs do, but a soul illness in many different ways. That time I started looking at the other Warlock specs and they actually looked really awesome flavour-wise (E.G. Destruction controls the all-consuming Fel Flames, and Demonology controls the variety (though not so variable, actually) of demons).

Main point here.

The speculation.

I like the current Demonology design very much - kind of like the master of demons, who summons different stuff from Twisting Nether to his aid. However, the thing I don't like is that it's mostly imps. Yeah, I adore imps, I love the Imp-losion and Imp Gang Boss cards from Hearthstone, but I feel that Demo warlock could make use of the other Twisting Nether inhabitants. For example, imp summons on direct damage spell casts is one of the best mechanics I've ever witnessed in WoW and that keeps me playing my Warlock. However, imp summons on Bane of Doom tick feel... Kind of not quite right, especially after what Curse of Doom originally used to summon. Yeah, the Doomguard, same as in Warcraft III.

My thoughts on improving it.

First off, Wild Imps is the greatest ability to ever exists in terms of flavour, so I'm not talking it at all.
Bane of Doom. It could proc to summon a Doomguard to assists you for a short time (just like the Demo 2p tier works right now), or each tick of it could stack a buff on you, which would summon a more powerful demon on your next spellcast (Doomguard or Observer, however Observer doesn't quite fit in my opinion).

It could even have a chance to summon an Infernal from the skies to assist you for a few seconds and then die (or explode on dying, dealing AoE damage).

It could also be more random and have a chance of spawning a random demon, which does random stuff (i.e. any of those I listen above).

It'd also be very cool if Demo warlocks got their own Grimoire of Service-like ability. For example, it would either summon a random demon to assist you (which would require Bane of Doom to work different), the demon would be different from what they are now. For instance, Observer could get more powerful with every spell you cast (since it observes and devours magic), Succubus would heal you/stack a shield on you, or (if we consider PvE here) just stack a damage buff on you, Voidwalker/Voidlord would use it's own HP to damage the enemy and explode when it dies.

Last but not least, a Felflame-like ability, which would have a chance to explode for 3 Wild Imps on a target. Could also be an Execute ability with a guaranteed chance to summon Wild Imps (or a random demon for a short time) on a longer cooldown, than other Executes (since, well, it summons demons - think of it as of extended Execute - probably somewhat similar to DK's Soul Reaper).

Again, these are just my speculations and I would be very happy to see any improvement on Demo Warlock flavour. There are a lot of cool Warlock cards in Hearthstone which could be made into spells in WoW. Most of my impressions were made exactly this way, plus remembering some classic Warlock spells from Warcraft III (oh if only we could get our hands on Rain of Fire, which summoned multiple Infernals...)

Here's what this post looks like on official EU forums

http://eu.battle.net/wow/en/forum/topic/14821092356