I think one of the biggest issues with this whole thing is the time-to-market. Lambdas are planned as part of Java 8. At the moment, that's in about a year from now.

Then consider when you'll actually upgrade your production code to use Java 8...I have a feel that by the time you see some stable lambda code in production (depending on how bleeding-edge you are), it will be quite a while.

Who knows by then how things will be. You might even be coding in Scala or Clojure...