Assymmetrical ships always struck me as something the Eldar would be keen on, although I have nothing to back that up.
I have a theory on symmetry with regards to space ship design aesthetics. I call it the 90/10 rule. For a ship to look cool it has to be 90% symmetric and no more than 10% asymmetric. Examples of ships that possess the required ratio of symmetry to asymmetry include the millennium falcon and modern aircraft carriers. If you get too much asymmetry, ships just don't have any sense of direction to them. Does anyone remember the borg ship for ST:TNG from the one season finale with Lore and the rogue borg? Too much asymmetry.
Please note that the 90% and 10% values are complete BS, and the rule could be called the 80/20 rule just as easily, just as long as the meaning is conveyed - major symmetry with minor asymmetry.
The DE blade wings must be large as it are their versions of sun energy collectors (sails).
My problem with that is the GW tends to create fluff to justify it's ridiculous models. The way I interpret things is that the designer thought, "hey, I know, I'll give it blade wings and that will make it look more dark eldary. Afterall, I work for GW, where putting spikes on things makes them evil, and the bigger the spikes, the evil-er they are."
I will not stoop to that level. I may give it blade wings, but they won't make the ship look like a grappling hook, and the guns and engines won't look simply tacked-on.
I'm sorry, I'm just not a big fan of the DE ships. I feel like there ought to be some relationship between them and the corsairs (at least). But anywho.