Even the writers took a cheap shot at the Ent-D crew in DS9 "Bar Association" when Odo reads Worf's security chief record to filth as casually as ordering lunch...and the one example that really sticks out is 'you let yourself get taken over by Ferengi rebels in a derelict bird-of-prey.' (Never mind that we can fast-forward to Generations where the Ent-D gets blown up by Klingon rebels in a derelict bird-of-prey...have we found the true Achilles Heel of the Galaxy-class here?)
Agreed the good concept got out-gimmicked by the fountain of youth gone wrong plot line. No one even mentions the fact that a respected, wisened Starfleet admiral literally tells his own beloved long-time wife,
right to her face and with zero remorse, "I got enough of the anti-aging drug for the two of us...and I took both doses." If I was Mrs Jamieson, I'd be calling a divorce lawyer and signing up for Star Trek: The Golden Bachelor. An unreal portrayal of total betrayal, very much glossed over.
The most important--I think--part of the story that truly gets lost: if the enemy of my enemy is my friend...you better be damn sure they're still going to be your 'friend' for the long-haul. We've seen enough examples of that go wrong in the last 20-30 years or so to let that lesson go unlearned. But that's all I'll say about that real life topic outside of the Misc or Neutral Zone boards.
Look, I like Lwaxana Troi. I know most people don't, but I do, and still I struggle with this episode. However, I am totally unwilling to put it on an all-time worst list. For one very, very good reason. Michelle Forbes, somehow, against all odds, was able to pull off a straight face while wearing the world's goofiest hairpiece. Just Google "Michelle Forbes Half A Life" and look at the image results. She deserves a trophy just for that.
So, my worst episode of TNG? Certainly not The Naked Now, Code of Honour, Justice, or Angel One. They've all become such caricatures that they've moved into pure comedy territory over the years; they make fun of themselves so well with no effort at all, so I can't include those.
I'll go with either The First Duty or Journey's End. It's not on purpose that they're both Wesley episodes - but it seems like Wesley had become the character the writer's room used to get a lot of their underperforming script ideas out of the way.