

"Legacy" is an episode that I'd like to think introduced Star Trek to what would become the biggest and most popular staples of the franchise in it's later years. Casting very attractive female actors and putting them in revealing skin-tight one piece outfits!

Good thing Trekcore hasn't caught up yet with it's HD grabs.
Yep. I'm betting someone in the higher up watched this episode and thought "This kind of stuff should be seen in every freaking episode!" and fortunately or unfortunately depending on your tastes or standards, they got their wish in the end.
Moving on. Legacy is a unique episode in TNG's run because it's one that deals with Tasha Yar's sister. First thing I thought of when learning this was "My god. Sisters do exist!", second was "She's a one-shot female guest star who's story will not end well" and third, "Why didn't Tasha ever mention her?".
The episode goes even further into Tasha's backstory by actually going to Turkana IV, the home world of Tasha that was mentioned in "The Naked Now". What's strange with the civilization aspects of this planet is that it's populated by war mongering, deceptive, violent, and *gulp* child raping....humans.
Ok, stop. Stop, stop, stop, stop, stop. Did this have to be that literal? I give credit to the writers for actually remembering continuity details from three seasons ago, but just listen to what's being said. These are people who have been alluded to raping children in packs. I mean, if they didn't, why would Tasha want to avoid them or even call them rape gangs? What makes this whole thing shocking is that the planet's residents are not aliens. They're ordinary humans who are under no influence of any kind. I can understand something like old people feeling the loss of their loved ones getting a slip, but this episode deals with issues that reflect the absolute worst aspects of humanity and the only person who has real issues with it isn't even human! I mean, what the heck Star Trek? You'll have characters sing and preach about how humanity is no longer a dangerous and savage child race, but you're happy to showcase a planet full of dangerous and savage humans.
The story, as much as it is, deals with the Enterprise attempting to rescue a crew that crashed on this planet and are being held hostage by one of the warring factions. Ishara, Tasha's sister offers to help with the rescue efforts. As the episode progresses, Ishara feigns interest in wanting to follow in her sister's footsteps and the crew pretty much fall right into it. So during the rescue effort, Ishara betrays the crew by taking advantage of their rescue to sabotage the enemy faction's generators. Data stuns Ishara, is sent back to her people and everyone talks about how disappointed they are in how Ishara was not like her sister. The episode tries to lighten this up by having Data look at the crystal she gave him, but it won't matter in the long run.
CONCLUSION:
For an episode that actually follows some continuity from earlier episodes, it's a pity it all ended up not going anywhere and ensuring Ishara's character would never be seen or mentioned again. I'm still surprised how nobody in this episode seems interested in discussing how this human inhabited planet came to be such a bad place for everyone and why the Starfleet, or the Federation doesn't do a darn thing about it. After all, the Prime Directive doesn't even apply because they're humans and it's obvious that there's suffering going on. This stuff is just weird.