Well it looks better. It's got some synergy which is good, but to be honest some of the cards don't provide enough value. I don't know if you're card choices are very limited due to budget but if they are getting some of the uncommons I mention below shouldn't be hard.
Slither head - dies to everything doesn't do anything besides chump and get you an extra counter. Strongly recommend switching to Experiment 1.
Sylvan Caryatid - not sure what it's doing for you in this deck. It doesn't support you're aggro plan. It's a ramp card... what are you ramping too though? you're not going to be able to hit the turn 3 monster like red/green. You're deck is an aggro deck that works off attrition. This deck should be able to keep resilient threats on the field and apply constant pressure. Sylvan Caryatid does none of these things. I recommend using pack rat or even, scavenging ooze if you can get them.
Under City informer - no, just no Seriously though, you're going to sacrifice a creature for some kind of mill? All this card does is help your opponent. There are any number of better 3 drops. Dreg Mangler, Varolz, lifebane zombie etc...
Jarad - he's okay, there are worse 4 drops. Corpse jack might actually be an okay 4 drop here if you go with more scavenge. However, I do like the reaper, she's resilient, but remember she's probably more of a 6 drop than a 4 drop. You want to be able to give her hexproof so she doesn't get removed, unless you happen to have multiples in your hand. In general reaper has to be answered.
Nemisis - for a 6 drop he lacks a lot. He could potentially come out earlier. I'm not totally apposed to the idea of the inclusion of the nemesis in the deck, but if you play more scavenge he's probably not the way to go. Also, milling yourself with the informer to enable this, is not a good play. I think if you want to run this guy he comes down to a 1 of maybe 2 of. He could surprise some decks, but honestly, he's probably just a target for removal. I think you need more threats, not bigger threats. Lotleth and Exp 1 can get pretty big I don't think this guy is necessary. You'll almost never be able to actually hard cast this guy. Getting to 6 mana, even with ramp off of 21 lands would be really hard.
Elvish Mystic - I'm okay with this, if you have a good 3 drop or 4 drop to get to . Right now, I'd be embarrassed to drop an informer turn 2.
Night Howler - really if you cast him turn 3 he's probably at best a 1/1 and if you ramp with elf and are able to cast him turn 2, you probably won't be able too with nothing in the yard. Again, any of the other 3 drops I mentioned would be better.
Grisly, Commune, Filth - you need more 'stuff" these cards don't provide enough of what you need. Grisely is fine, it can help you if you get mana screwed and get you a creature. I'd stick with it. However, you need some removal of your own. You really need some number of Hero's Downfall, devour flesh, doomblade or ultimate price. I think for this deck you want cheaper removal, so devour flesh, doomblade, ultmiate price. Hero's downfall maybe as a 1 of, 2 of if you have them for planes walkers. Devour flesh can also help you gain life if you need it.
Remember you're a BG aggro deck right now, not a ramp deck, not a mill deck. You don't need to try to dump everything into the yard. That will happen naturally through combat/removal. And if you're creatures aren't getting removed then you're already winning and don't need to fill up your yard. You can still get synergy off the yard but it needs to be part of the plan, not the only plan.