Phazael
This is my current refined 2k competitive list that I have settled on after some playtesting:

HQ:
Farseer- Runes of Witnessing, Runes of Warding, Fortune

Elite:
9 Fire Dragons + Exharch with Dragons Breath and Crack Shot
-Wave Serpent w Scatter Laser, Shuri Cannon, Spirit Stones, Vectored

8 Harlequins + Leader + Shadowseer all w Kiss

Troops:
9 Dire Avengers + Exharch w 2 Avenger Cats, Bladestorm
-Wave Serpent w Scatter LAser, Shuri Cannon, Spirit Stones

9 Dire Avengers + Exharch w 2 Avenger Cats, Bladestorm
-Wave Serpent w Scatter LAser, Shuri Cannon, Spirit Stones

Fast Attack:
8 Warp Spiders + Exharch w Power Blades, Twin Spinners, Withdraw

Heavy Support:
Fire Prism w Holo, Spirit Stones

Fire Prism w Holo, Spirit Stones

Fire Prism w Holo, Spirit Stones

Pretty much a straight forward mechanized list with some clowns for CC power and to draw fire. Six Grav tanks with a combined 21 S6 shots a turn (plus prism cannon goodness) pretty much destroys anything resembling light vehicles or infantry. Drive by Dire squads are good for sniping survivors and squatting on objectives and the fire dragons are a solid answer for just about any heavy hitter unit out there. The Spiders are there to counter things like Land Speeders and assure victory over armies that cannot easily deal with them, like Tau or IG.

My biggest issues are facing Thousand Sons (multiwound maries are hard to kill with prisms and clowns) or Rokkit heavy ork lists (which can poumd my skimmers into the ground), but lucky neither of those lists are very common. The list is particularly strong against pods, which are common in my area. The only remaining adjustment I am considering is to drop the Fire Dragons and transport for another set of clowns and Seer. While the Fire Dragons are very handy, I find that my opponents tend to quickly eradicate them (or worse, send a single C to grind them down over several turns) after they erase something from existance. The only reason I have kept the Dragons for now is that they are (being mounted) a much quicker threat response force than the clowns.

Q: So who does the farseer fortune? the harlis?

Correct me if i am wrong, but the hariquins are basicaly the only infantry on the ground. That and the farseer. If the harliquins can always be ignored, then that means the farseer is the next legal target.

Of course i am making a few assumptions here, and this is only until you deploy some units out of the serpents.

A: He joins the squad, normally, and therefor benefits from the Veil (since it is a psychic ability conveyed to the entire unit), but you lose hit and run while you are doing this. Given a good opportunity and need, I will often break off the farseer solo so that the clowns can bounce around from unit to unit, but that usually happens later in the game.

The dragons are in a serpent, they just get smoked the moment they step out to erase something from existance. As in, people will actually stop shooting at the clowns for a turn to wipe them out. Doesn't seem to affect my ability to win, but it would be nice to have more squads that live to the end beyond the Prisms and the odd Dire unit.