"Sir Weyland, the runner is nearly at the gates; the men are growing restless. What is your command?"

"Fear not Sir Lancelot, this operation was nothing more than a Honeyfarm all along! Fetch me my Snare and our strongest catapult, we'll send them clear back to Space Camp!"

"After careful consideration, we of the jury find the defendant, Mimic: Not Guilty!"

"I hereby award the defendant his counter-suit of all 7 credits used in legal defense in full, to be paid by the prosecution." - Zealous Judge

Did they forget about Mimic when they thought this up? —
I think this is like the tales of what Monolith once was... at one point this was way overpowered and the playtesters said, "Either drop the strength from 5 to 3, raise the rez cost from 4 to 7, or let the runner choose the card," and they did all three. —

After playing with this card for a little bit, I can confirm that attempts to make Slee's Pachinko Parlour with cheap ICE that the runner normally doesn't have to break are largely doomed to failure. She just doesn't cost enough to trash to protect herself, and if you try to run her out of faction in CtM or Industrial Genomics to rattlesnake people away from trashing her you'll run right out of influence to do anything else.

Yes, you can protect her in what would be your scoring remote. Yes you can make someone pay 5 to get past a free to rez Bandwidth to get to your HQ safely, but that's exactly what they'll do if you turtle behind porous ice without a place to advance agendas, and Slee will stay sad at 1-2 power counters until a Political Operative comes to take her out of her misery. She just isn't quick or dependable enough to build a kill strategy around. If she ever becomes threatening enough, they'll come kill her after they've amassed the credits to do it properly, Prisecs be damned. And you'll be stuck trying to sneak out agendas on a secondary remote while your centrals are spread thin.

However, that all being said: I believe she's still marginally useful. More than some give her credit for.

The best use of this card to me seems not to build a deck around (though you will be sorely tempted to), but rather as a way to threaten the runner's sense of security in facechecking ice until she is dealt with properly as a way to buy time to set up a proper Glacier. Throw her out in her own remote with a Prisec or a Mumbad Virtual Tour. When the runner feels pressured enough that they no longer feel safe facechecking new ice on your centrals, they'll come to trash her and give you a small scoring window to work with. Sometimes, that's all you need. Aim not to ever kill them with Slee, but instead to put a mandatory break period for the runner somewhere 3-4 turns out.

There were a few, brief, shining moments in my head the first time I read Slee where I thought I could Dedication Ceremony a Mumbad Construction Co. straight into Slee. But sadly 'tis not to be. If for some reason there are ever just one or two more cards that are willing to spread a power token or two put this card back on your radar though.

As of now she's not good. But at least in concept she's fun.

It's important to mention that while Slee is very fiddly when you use her with porous ice, as you mention, she still has amazing synergies with cards like Little Engine, or even the moderately taxing Data Ward —
In-faction Hive should always get a mention. Full counters if face-checked. Can't be denied its potential. —