Acc prob with my dark/regen ..Why?

Why is it? Well, it's possible that you're coming off of characters with sets that offer extra inherent accuracy. Dark Melee is at base accuracy for the most part. It's also possible that now that you think your accuracy is bad, you're noticing the misses much more than the hits. To confirm your suspicion, pull up your combat attributes, and monitor your last hit chance. If it's firmly 95%, you don't have a problem, so there's nothing you can do.

If it often dips below 95%, then it's worth addressing. For IO solutions, I guess it depends on what you consider spending craploads. I always slot a Kismet unique, which will probably run you a few million. But you should have a few million by now, and I consider reliably hitting to be influence well spent. By your level, you could also consider frankenslotting your powers with cheap multi-aspect IOs from a mixture of sets. In your case, most of them should have accuracy as one of the things they enhance. Going that way isn't much more expensive than SOs in the long run, but it does take some time. If you simply want to avoid IOs completely, you can pick up the Leadership pool and get yourself into Tactics. Also, use Soul Drain in crowds. It'll boost your to-hit a lot when saturated. Pick it up if you don't have it yet.

Don't we get one of these threads at least once every Issue?

Let me say this outright: DM is no less accurate than any of the other sets out there with baseline accuracy (every Scrap set except for Kat, BS, and MA). With the acc slotting you're saying you have, the only difference you would see between Dark Melee and the "more accurate" sets (Kat, BS, MA) would be a tiny difference when fighting +3s and higher.

I'm pretty much going to tell you that it's due to your own flawed perception rather than anything substantive. You're probably missing with Shadow Maul and seeing yourself whiff for a good 3 seconds straight (which is what it is designed to do because it only makes the tohit check once when it is activated) and then assuming that you're missing a lot. Conversely, you could just as well be assuming the set is less than accurate because it's not covered in AoEs, which provide a large smokescreen for misses.

Except that as everyone well knows, Herostats actually improves your accuracy, which is why it won't confirm the known accuracy nerfs the devs put in every issue. To avoid problems, you need to run Herostats in the background at all times.

When are the devs goiing to get around to nerfing the clearly broken buffs that HeroStats gives? Enough, I say!