Hmm, Fast Attack has some serious problems nowadays. Here they are:
Raveners: They're awesome looking, but can easily be outperformed by a Warrior for about 2/3 of the cost. The only thing the Warrior can't get is fleet or deep strike. As far as deep strike goes, they're just too vulnerable. Two wounds and a 5+ save means a moderate breeze can destroy them before they can even do anything.
What Raveners need is either to be tougher, or to be a lot cheaper. That's really the only thing they need to be fixed. Also, I'd like to see the build-a-bug system applied to them so I can upgrade them if I wish (same with Lictors).
Gargoyles: I have never used them. I am a man who actually owns a full unit of 10 Wraithguard, and I can't bring myself to invest in a unit of Gargs. They're supposed to be a swarm unit, but at $8.50 a head that's their biggest problem. What they need to do is make them plastic, cheaper (points and $$) and make their bioplasma a shooting attack, not a close combat attack. Give 'em a flamer template (perhaps every 4 Gargoyles give one flamer attack at S4 or something).
My prediction is that taking a winged Hive Tyrant will unlock Gargoyles and winged rippers as a troops choice.
Spore Mines: Man I love spore mines. Even if you miss you still get something. Alas, they suffer from several problems. The first is their blast size. While 5th breathed new life into the small blast template, I think the frag mine needs to have a large blast.
Another problem, the obvious one, is kill points. In my local group, we do not count them for KP at all (nor can they run), but it would be nice to make it official. After all, the entire point of a spore mine is to blow up.
In other news, I finished my Malanthrope and am almost done with the Blastscape. Pictures coming soon.