Its got a solid 'core' but several faults
IMHO, my suggestions are:
- Farseer is a good choice and could benefit your army, however you dont need a 3rd Psychic power as he can only use 2 a turn (I'd drop guide if I were you) and make sure the two powers you use can actually be used together, eg. not 2 'shooting' powers... Otherwise it's good, although you may want to drop the Spear?
- I personally like Banshees and they work very well with Doom, I'd assume your playing
Meq's? If not I'd swap the
WS's Starcannons for Shuriken cannons to keep him cheap and cheerful and acrobatic isnt really need for the exarch
IMO
- Fire Dragons are a solid choice as always, although I would favour a
WS over Falcon as with a wave serpent you wont be sacrificing too much shooting in order to get the Fire Dragons where they need to be.
- Scorpions seem OK but not really needed if you are facing
MeQ's, and even so I'd drop them in favour of Dire Avengers. Otherwise theyre set up well...
- Your Gaurdians set-up is good, once again, Spear isnt needed and you may also want to drop the Warlock in favour of simply putting them in cover!

I feel a Warlock with conceal is better ran with Jetbikes...
- Your troop choices are largely OK, however I do feel you are definately lacking in troops,
I would recommend atleast one 10 man squad of Dire Avengers in a Wave Serpent, they are adept at holding objective and can escort the farseer who could guide them and doom the banshees targets to deadly effect?
- Your Falcons set up well, I'm not sure however whether a Fire Prism would be a better choice? as theyre cheaper and have more potent firepower...
- as for the fire Prism I dont think you need either Holofields or
SS's, generally you keep them at such a distance where they dont get shot too much!

and if they do then theyre cheap enough for it not to matter!
Anyways, I hope that (albeit long post) helped! Good Luck.