When using Google, I find multiple suggestion threads dating back to april where people suggest fixing the herb sack. None of these suggestions have been declined or accepted.
I bought a herb sack in my first week of playing (around the start of may). Especially as a new player, it takes a while to farm 2k slayer points. I wasn't aware of the herb sack not working, so imagine my disappointment when I did (and I'm sure I'm not the only person who this happened to). 2 months later, the herb sack is still sitting in my bank, constantly reminding me of my misspent slayer points.
While I'd like to see the herb sack fixed ASAP, I have no idea about the complications of implementing a fix (and if there are even time/resources to do this). If there's no way to fix the herb sack (short term), then at least remove it from the slayer shop. If it's decided that it can't be fixed at all, please find a way to reimburse the 2k slayer points to players (maybe allow them to sell the herb sack back to the slayer shop?).
I'd love to see what other people think about this.