Ok remember that bright lances are only better than missile launchers against AV13-14. You know the people in your area better than me but I know I often prefer to save the points and go for missile launchers. 1 Bright Lance per 750 points is my rule of thumb but hey, you need to make up your own rule there.
Guardians are better with a heavy weapons platform with multiple shots. Usually a scatter laser for smaller guardian squads (hang back and shoot a bit) and a shuriken cannon for large squads (all hell across the board). Conceal Warlocks are also great for them.
Your dire avengers are fine except for 1 thing. Every single avenger squad should always have bladestorm, its what makes them.
I hate doomseers but thats just me. Mind War all the way. Doom does help your army a lot I guess due to the mass of shuriken catapults.
Going to 1000 you have to make an important decision. Do you want to go mechanised or not.
Mechanised will involve buying wave serpents for what you already have and more aspect warriors in wave serpents. Then either a falcon or fire prism (or 2).
If you don't like the idea of mechanised though I'd say add either some infiltrating scorpions OR some harlequins. A 5 man squad of pathfinders. Another Wraithlord and either some warp spiders or swooping hawks. The idea behind this is to simply shoot the enemy to death whilst they can't catch you. If they do get into cc then its with scorpions or harlequins and not a more fragile unit.
In the old codex Ulthwe had special rules but not anymore, generally all they are now is a colour scheme and a style of play (Ulthwe tends to be more of a foot swarm eldar).
Our anti-marine weaponry is now really our aspect warriors and our harlequins. Don't look to the starcannons like we used to. If you want to mow through tactical marines quickly simply charge them with any of our cc specialists (we should win) or don't let them get close, i.e. rapid-fire range.
At the end of the day the additions I suggested are just there to show a more powerful list. It's up to you to decide which units you like and what you want to buy. You must choose between mechanised or balanced though.
