Moved from the other thead...
Not that this has anything to do with Nids v Marines at this point, but I fail to see what the infantry reduction/aircraft increase will accomplish.  I have a problem with the entire concept precisely because I don't think it will do anything.
The fact is that despite the arguments to the contrary, most SM lists don't take huge amounts of air assaults and do take 1-3 ground formations of Tacs, Devs or Scouts.  I just went and pulled some batreps for example armies to see what would happen to their point cost if no force changes were implemented.
This one with 2 Thawks would be the same.
This one with an LC would be 100 points cheaper.
This one with 1 Thawk would be 25 points cheaper.
This one with 1 Thawk would be 50 points cheaper.
This one with 2 Thawks would have come out the same.
My typical marine force with a reasonable deepstrike component of 1 Thawk and 1 Termie formation would be 50-75 points cheaper from 2-3 Tac/Dev formations.
(there were a couple others that I didn't include because they were odd scenario games)
So, you're giving the SM players ~50 point average discount even if they make
absolutely no changes to their army composition.  I admit that's not huge, but it still begs the question of why they deserve a discount.  On the flip side, none of them would have gained more than 100 points even if they removed all air assault from their army.
"Gee... I get 50 points for doing nothing, or I can scrap all my air assault, trade it for ground pounders and save maybe 150..."
Where is the incentive in that?  How is that going to be enough to encourage marine players to make substantial changes to their force composition?