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So one of the guys I play with really likes to drop pod Space Marines. Typically his tactic is to drop pod dreadnoughts and infantry in between buildings to block opponent vehicle movement. Nothing like boxing a leman russ in 1st turn. Another tactic is warp in a dreadnought with a multimelta so it can kill a transport unit of more value.
Anyways wyches really got a leg up on antimech in this codex. Let's say you build a wych squad with shardnet and impaler and haywire grenades. Some how a S3 wych can entangle a dreadnaught and lower his attacks to 1 unlike the previous codex. Next a wych can actually use haywire grenades and glance or wound it. Unlike before where it had to be immobilized. So wyches with options > dreadnaughts in CC
I've already tried this set up already on a 5 man squad in a venom and it's not a bad idea just remember to stun or immobilise the dreadnought, or your hitting the thing on 6's. Even if you do fail to kill it at least you should hold it up for a few turns. I still need to test it out more myself so let me know how you go.
I run my wyches at 8 strong and now that you mention it, my play testing is showing the wyches as eventually winning. Of course, this is a sterile environment in which it's just my 8 wyches with 1 impaler charging a Dreadnaught. I am already sold on the impaler and haywires are already being bought so it was just a matter of rolling the dice.
So yah, I am liking the option however most of my testing had the unit tied up for several turns - some short, some very long so if you do not mind losing a scoring unit to an elite unit the idea is fine. For those who have better luck with "darklight" guns I would still advise shooting it first in most cases and only assault one if it's going to mess up your plans.
"On a hunch, I melted them down and inhaled the fumes and read the dark eldar codex again, AND FOUND A BUNCH OF NEW RULES HIDDEN BEHIND THE OTHER WORDS..." [Gardeth on modelling & interpreting the DE Codex]