I agree with you that the dretch should be boosted or rifle nerfed (rifle as a free weapon is really too good in my opinion) to make the start more balanced. Other than that, disagree. Turrets are fine as they are (just place them well!) and maras too.
I did some more building as a human in 1.2 and I'm starting to understand the new rets a bit better. I like how they force the H-players to not rely on base defense so much and they DO work quite well when placed properly. So, on that point, I must concede.
I think what a lot of people don't realize about the opening-game balance of 1.2 is that, because the Dretch can longer attack structures of any kind, the game itself still relies on the humans coming out of their base to attack.
Sure, the rets take longer to spin up so the H-base itself is not as impenetrable as it once was. But, with the right builder, humans can still camp as long as they're willing.
Let's say that a single naked S1 human is charging the base of a bunch of noob-aliens who can't Dretch for shit.
In this scenario, the naked human can walk into the A-base and theoretically destroy everything in his path:
Their tubes, their spawns, even the Overmind itself.
Now flip these factors so that the humans are noobs and one leet Alien player is on the attack. No matter how skilled of a player he is, if he's a Dretch, he still can't actually effect anything. His best bet is to get a few kills and evolve into something that can actually effect the human base, but then he still has to retreat out of range of the humans to evolve.
In 1.1, this was totally justified by the fact that Aliens were just a bit too good at pwning and even decent humans needed a base with some breathing room if they were going to stay alive in S1. I also understand that a lot of the changes in 1.2 were meant to address exactly that issue. I just think the alien nerfing was a bit too much compensation and now their class is just as much the underdog as Humans were in 1.1 games.
And what nobody really seems to want to address is the issue of weaponry. Sure, Alien attacks SOUND cool on paper. But they are another thing all together to pull off, in game. I mean, real humans (as in us) invented ranged weapons for a reason: It made warfare so much easier.
If the other guy has to come right up next to you to hit you and all the while you can just blast him with bullets (or lasers, or lucies, or fire...), that other motherfucker is as sure as dead unless he is:
1.) Fast
2.) A Good Aim
3.) Great at blind dodging with his back turned.
Regenerating health wouldn't hurt either.
Though, don't get me wrong. These same reason are why I LOVE playing Aliens. When I pull off a 3-kill Mara-slaughter in the A.T.C.S. hallway while dodging fire from two different lucies and an MG and I manage to retreat with only 3hp and like 7 evos, I feel pretty damn badass.
Still, that's why Aliens require so much health to be a viable opponent. If the aliens can't stay alive long enough to withstand more than three seconds of a single enemy's attack then, to quote the great American writer William Faulkner, they're all just "sound and fury, signifying nothing."
...Okay, I think I MIGHT actually be done trying to explain myself on this one. I hope I am, anyway.