30K Marne Legion armies viable in a modern high powered environment?

I think so.  The more I look over it and the more I piece together what I could actually field myself the more impressed I am with what Forgeworld has come up with here.  Comparing it to all of the current Marine Codices I find a LOT more options.  5 ACTUAL Troop choices AND Terminators are always scoring.  Yes, 3 of the Troops choices are "support" and so cannot be used to fulfill your mandatory Troop sections, but so many options...  And no silly hoops to jump through to unlock options.  Looking at Blood Angels, while they have lots of Troop options, really only 3 are Scoring and so viable.  2 can never Score, and thus are basically Elites, and mostly useless in 6th Edition.  DA and normal Marines CAN unlock other things as Troops, but basically, Tactical and Scout Squads are it...  With the growth of "Ignore Cover", Scouts are a difficult choice from a survivability standpoint...  Tactical Squads are "Eh" at best.  4's across the board for stats and 3+ armor are nothing special these days, and the Bolter is extremely substandard.  Not enough Heavy Weapons in the Troop sections, not hugely mobile and not particularly survivable.

Looking at the Legion, I have options for  things like a Tactical Support Squad with up to 10 guys, 9 armed with Meltas, Plasmas, or Rotor Cannons or a Volkite Calvier.  The Calvier is a 30" range Str 6 Heavy 2 with the potential for extra Wounds...  But basically, 30" range Str 6 shooting :-)...   Troops, and the Augury Scanner is cheap...  Allows the use of Rapid Fire or Heavy Weapons as Interceptors against Deep Strikers...  So, that could be brutal.

Almost every SGT can be upgraded to Artificer Armor, and most line squads can be up to 20 members...  Things like the BA Medics are standard things.  So 20 FnP Marines should be able to hold out a while...  NOT cheap, but again, something that you can see in a more limited and limiting fashion in modern (ish) codices...  And the Spartan Class Raider can carry 25 models, so the FULL Squad along with ICs...

I guess THAT is the frustrating thing about the 30K vs 40K comparisons...  Using just the basic Legion list as a basis for a list as I want to field it, I can actually make just about ANY of the modern Marine based armies.  And better I think.  Honestly, I think I can field a Legion list that can go toe to toe against the Tau/Eldar silliness that is currently dominating the Internet/Tournament scene...  Scoring Terminators, cheaper Land Raiders, which CAN be immune to Melta and can be Dedicated Transports...  So, no new stuff, and perhaps having a difficult time with an overload of Fliers.  OTOH, the Fliers will likely have a hard time dealing with the Land Raiders.

:-)  Guess I'll break out the 3 ancient Land Raiders and see what the Legion can do this week...  Glad the old Army Builder program had the Heresy stuff in it these days...