Actually, I think a lot of things could be solved by just increasing the point value of Lesser Nodes to 50 points. This makes the Greater Node a "deal" for the same number of wounds.
Garrisoning with Lesser Nodes really shows the "infestation" nature of a Tyranid attack and I don't think people should be forced to teleport them. I probably lose 75% of my teleported Nodes before they get a chance to spawn, the threat of Bugs showing up in their backfield is just too much for most people to allow. And then that's just giving your opponent a chance to get closer to the BTS goal.
As to not having Rippers? Well, I think every Tyranid organism should be dangerous and a single 6+ attack for the Lesser Node hardly seems overpowering, there's just a few hundred Rippers there...
Making them like a "Deathwind" attack would be too much I feel.With a points increase, I think they'll be fine.