Welcome to Advance Tactica of Ghost Warrior Armies.
I’m rather sure that you are quite proficient in using those wraithguards or at least have a darn good familiarity with them now. If not, you need to read Ghost Warrior Army Tactica.
This topic is to insert Independent Characters in your list be it a farseer to Eldrad or even an autarch to Yriel, even a Phoenix Lord will do too.
First, look at your list and or even ask a few friends that you know who are knowledgeable, even us here in the PoC: Iyanden to see what you are lacking in it, since your own vision might be biased at this point.
Second figure out if this is viable, if you have the miniature(s) or not.
Third address the possible problem by alternate means or direct means.
1. Alternate means = new units either by switching or cross cutting points from other units.
2. Direct means = this is the actual Advance Tactica, insert your high powered CC characters as a support for CC counter or even as a torpedo to attack other units.
Eldar Independent Characters usage:
Eldrad – he is probably one of the best solution if you need 2 farseer but only have 1 open slot left.
Yriel – awesome fluff character, but he’s also quite dangerous in CC support.
Phoenix Lords – just about all these characters are deadly as an add-on to a wraithguard unit.
Avatar – he doesn’t join any of the units but he’s a grave threat to anything your opponent does, so he becomes a shooting magnet.
Will add more, just sleepy at the moment.
Understand that most of you are afraid to lose that Spiritseer, but to save a wraithguard to keep that T6 is valuable. Although, caution yourself in receiving those Invul saves esepcially if the unit isn't under a Fortune Power even then it's a 4++ roll meaning still a darn good chance to get killed.