Well I posted the strong points and the guts of the list. I went through things for a player to keep track of (like keeping those commissars to the front of the mob) and what kind of support units would really help the mobs. Now I need to talk about what kinds of things could really hurt it.
1. massed templates will ruin this lists day. Another guard army with twin manticores or lots of russes will melt it.
2. anything that can reduce leadership like a psyker battle squad could make it run, as they over-ride the stubborn rules.
3. high initiative hordes like hormagaunts in the tyranid list would eat this alive. they go first all day long, and when coupled with paroxysm will make you hit last and hit on 5s.
These are just a couple of examples, but are enough for me to not try this list, even though I likely could field it now with the models in the box downstairs. How do you counter these big holes? you tell me. If i can find a suitable counter to this stuff I might try to make it work. Besides, once I see the look on my opponents face as 150 guardsmen come running accross the table it might be worth it!