Thanks a lot for your answers, and sorry for replying late: I was out of the country.
I have finally acquired my fantastic second-hand Wraithlord. Man, is it huge. I am sure it will look great on the table.
Partninja, thanks a lot for your thoughtful analysis. Regarding your comments:
2) I have very much liked the idea of using Rangers AND Guardians. At first I was a little reluctant to use the Guardians (mainly for Fluff reasons, with Yme-Loc being an underpopulated Craftworld which maybe could not afford to send troops to combat), but I see they have a lot to offer strategy-wise (as magenb said), and with all the Heavy Support I already have, the Yme-Loc feel will still be there. Moreover, Craftmen carrying around the HW Platform might be, in fact, as Yme-Loc as it gets.
3) It sounds reasonable. It seems I will have to try different Equipment options on the Prism (CTM, VE, Spirit Stones) and see which one fits more with my playing, but I do feel the S. Stones might come in handy, and won't depend on wether the Prism has moved or not.
4) I will trust you on removing the StarCannons on the WL. I was strengthening power when quantity and mobility might be better for a 1000 points list.
1) This new list looks a lot better than before to me, both in damage outpout (as you said) and flexibility. I was not getting the same points as you though, so I have had to cut down a couple Avengers to fit everything inside.
8x Dire Avengers + Exarch with 2 Catapults (112)
10x Guardians + Shuriken Cannon
Wave Serpent: Twin-Shuriken Cannon, Twin Sh. Catapult + Spirit Stones (139)
Wraithlord + 2x Catapults, Glaive, 2x Shuriken Cannon (133)
Fire Prism + Twin Shuriken Catapult (160)
Regarding the Fast Attack units, it seems it is going to be my next step. However, I still need to paint lots of stuff and even GET the rangers and Guardians, so I will have lots to do before reaching the 1000 points army anyway. Nonetheless, I am already thinking that, to keep things as Yme-Loc(ish) as possible, the new units would have to be bikes. Shining Spears look promising, but that joust look is a bit unappealing to me.