The thing about customization is the eldar are exactly the same,and they are already in, so it shouldn't be an issue. All howling banshees, fire dragons, ect have the same damn weapon.
Confirming. We have been brainstorming for quite a lot of time about how to have Necrons in EC in a balanced and enjoyable way. In my personal opinion, I think all races can be implemented and balanced properly: it's just a matter of thinking.
Can I see a summary? IMO, SMs, CSMs and Orks will be close to each other with ranged Tactical, melee Tactical, melee Jumper, Heavy and Healer. The Eldar will be different though, because instead of few versatile classes, they will have more and specialized classes. Same could be done for Necrons. There is no need to build Necrons around the layout set forth by the SMs/CSMs. If the Craftworld-Eldar are allowed to have lots and specialized classes, why not the Necrons?
But the Necrons attack very differently. They march in phalanx and shoot their gauss cannons. They are mostly moving slowly and don't use cover, because they won't die anyway. You'd have to make Necrons act like they are Space Marines and propably make them feel Unnecrony. I'd rather have them as PvE faction where they can approach in big numbers and march at me like an unstoppable force... instead of shooting running players without any kind of formation.
Simple solution: - Necrons are slow and tough. - Necrons have a ressurection-bonus when marching as a group. (Even higher when a Necron Lord with a Ressurection Orb is closely nearby.) - A Necron-character has an additional toughness-bonus when he has a specific distance towards his nearest team-mate. => Necrons can't sprint from cover to cover. But if they have the numbers and the discipline, they can assume a line-formation, a simple quadratic grid-formation or a hexagonal formation and now they have so much toughness that they can "charge" across open terrain and steamroll everything in their path. (Counter-strategy: Try to break the Necron-formation by concentrating fire or sowing confusion.) You can go solo as a Necron Warrior, though it's not recommended. You can play Necrons like a wild horde, though it's not recommended. You can play Necrons like Necrons, and now you are a merciless, indestructible wall of disciplined, undead metal.