Umm I went for WS. I just wanna say we have a lot of average armor troops and while I like WS... If it takes the place of wraith-anything, I'd be disappointed. If this was different, and my favourite, swooping hawks hadn't been implemented, I'd STILL prefer wraiths to them. And I don't even like them that much... But they are a necessity.
Well if it helps, no-one currently has an equivalent. The best armour in the released classes is the Space Marine/Striking Scorpion with power armour (or equivalent), same as the Warp Spiders IIRC. Wraithguard will be announced right along side actual Terminator information I expect. They won't add a 'Very Heavy' unit to one force and not the others. As for the poll, I actually voted Shining Spears. Mainly because I really want an excuse to swap my allegience from Second Favourite Craftworld (Biel-Tain) to Favourite Craftworld (Saim-Hann) and the Shining Spears would actually add a unit justifying the presence of S-H as a faction. Currently the closest they have to appropriate representation is Warlock-on-a-bike.
From a purely gameplay perspective I'd much rather have a Warp Spider at my side more than anything. The ability to sew confusion and panic alone deep within enemy lines will make my job as melee easier.
Seriously, however, I would like to see Warp Spiders. I love the idea of them. "Hmm, we're relatively slow, lumbering infantry in an army that favours swiftness. Seems a bit lame." "Well, we could get long range guns, then it wouldn't matter." "Naah, those Reapers guys have got that covered now." "Damn. Wait a second...what about PERSONAL TELEPORTERS! It solves the problem and makes us looking daringly reckless. We'll be fighting the ladies off with sticks!" "I like it. Strap me in and smoke me a Ky'pah....I'll be home for breakfast...."