Armwaving, n. - Arguments with which one disagrees, while being unwilling or unable to advance factual or logical grounds for such disagreement.
Engines - could you elaborate a bit on "pushing the envelope to a high degree in terms of TW"? Because the F135 weighs 6,500-some pounds and puts out 43,000 pounds, which translates to a nonstellar 6.6:1 (the F414/EJ200 are around 10 and the GE F110-GE-132 is about 8).
I've heard it suggested (recently from a source who really ought to know) that there are stealth and thermal management features in there, and the extended jetpipe, but (to paraphrase Elvis) that's still a hunka-hunka-burning-engine.