So does that mean you'd ban warfirged for their construct immunities? Not that I'd want to play one as a conduit anyway, but it's an example of a LA 0 race that gets a ridiculous amount of immunities for the relatively low cost of reduced healing from cure spells. That doesn't make it right, of course.
No Warforged are fine.
A human with the Product of Infernal Dalliance feat is better than that plant race. Free FoM > shitty DR. They both get a bunch of immunities based on type.
You are an idiot. Immunity to Poison + Freedom of Movement is not as good as DR 10, Immunity to Poison, Sleep, Paralysis, Stunning, Polymorphing, critical hits (and by extension SA and DA), and mind-affecting effects, and also +2 Wisdom and Con on top of that for a Wisdom based class.
In practice, saying +2 Wisdom and Con, Cold Resistance 5, Low Light Vision, and Sustenance is worth a feat is probably wrong, but pretty damn fucking close. But I don't care, because I don't want people making up homebrew races and then making me figure out how to balance them, because that's stupid. If you think being Human with Infernal Dalliance is better, then suck a cock and do that, because that's an actual legal choice that doesn't make more work for me.