I can't really decide on one or the other. My main problem is that I don't know how we are going to implement the shadow units exactly.
I think I like the option offered by T_F about having one shadow civ, that starts as Angband and later goes over in Mordor. The exact workings of that should probably left to a next release and if we decide to it this way a single shadow civ is most wanted for now. Discussion how we want this should probably take place in another thread. That won't stop me from posting my ramblings here though, as it is relevant for this discussion and I can repost it once we start discussing the shadow civ at length.
>> One shadow civ is good, as there ultimately there was always one Valar behind it all. However, after the first age, his direct involvement with the world stopped and his second in command took over. What I would like to propose is a shadow civ that starts with Melkor/Morgoth as a leader which can build Balrogs, Dragons, Werewolves, etc. These would be powerfull units and as long as Melkor is in charge they can be build (some to a limit (Balrogs eg) some indefinately). A hero unit, Sauron, can (must) also be build. However, upon reaching the second age, Melkor leaves this world (his king unit disappears), the Hero Sauron becomes king and there's a leader switch from Melkor to Sauron (with different traits as well). With Sauron as leader, the shadow cannot build the 'Melkor' units anymore, that is, no Dragons no Balorgs etc. The existing Balrogs and Dragons either go barbarian immediately or have a chance to go barbarian every turn(Shadow must be friendly with Barbarian for this to work), to show that Sauron doesn't have the influence over these creatures that Melkor had. With Sauron as a leader, the Shadow has the capability to create/invent new evil creatures and move forth along the techpath in general and some evil techs in specific.
What I like about this, is that it enables the possibility to stay with Melkor throughout the game (don't advance to the next age, his units are quite good and if he stays in the first age, he doesn't have much else to do then build units, so his number should make up for any quality problems). It also enables a Sauron only game through starting in the Second Age of the Stars. And it follows the book quite closely, which, though we want a 'what-if'-Arda, has its merits in this case.
<<End of rambling
). Quendi definetly an improvement so no argument there. I read through Elda Kings arguments and I think he raises valid points. I'm still personnally in favor of two civs but I can understand his considerations. It is a difficult decision I think. 
