LED does not feel combo to me, since you are playing off the top for the most part. I guess part of my question would be how many cards are you holding in hand on average and saving for later vs how much are you just trying to draw gas to make things go.
There's basically not any reason to hold anything in your hand. You're kind of playing everything you can cast, whether you have a combo draw or an aggro draw, so that part of LED isn't really a problem. My concern with LED is that it's "win more", only working with Forge which is probably already going to win you the game whether or not you have LED.
This is different than Cranial Plating, which can do something with Memnite or your other threats that they can't do on their own. Plating probably turns your 7-turn clock into a 2 or 3-turn clock, but LED turns your Forge from a 1-turn clock into ... a slightly more consistent 1-turn clock. It's a lot less bang-for-your-dead-card. This is all conjecture though, if it turns out that LED or another pure-combo card consistently speeds the deck up a turn, then it's probably worth it.