There's something I'd like to mention.
This is not a problem that just recently was patched in, but instead it's a problem that already was in the game for years. There are tons of oskills. Only a percentage of those oskills are actually good to use as a main attack like whirlpool, ancient's hand and Spin 2 win. Some are awsome as utility skills or as procs like Glacial Nova, or Punisher, Path of Flames and Wyrd.
But then there's also complete and utter garbage skills like splitfire (wow. You can hit 2 enemies that are in complete opposite directions. And in addition to that, the damage is really weak) Static Ward (low damage) and Clobber (I don't even need to point out why it's garbage)
I wouldn't think of it as a problem if there weren't that many oskills you'll never want to use. As someone who loves experimenting and trying out new builds, I simply want to have a better variety of oskills instead of the same old ones that everyone knows are garbage or at least worse than the skills you get from your character already. I know that you're limited due to the current D2 engine (I think I read in an old post by Laz that you can only have a certain amount of total skills) and I know that oskills have in general a real hard time since they can't be scaled well (they don't profit from +character class skill levels or have any synergies) but some of those skills really need some love considering that oskills are usually those skills that laz didn't find fitting aymore and just pushed them aside to be used as oskills. Especially skills like splitfire, which are so bad that I can't express it, need some love. You could make it work like Sporeshot for example or make it work like 2 hammers of zareae traveling in opposite directions to make it work with the name. Or you could simply replace it with something better.
Imo these skills definitely need some kind of rework (those are all the skills I tried out and didn't find useful enough to make it worth using them):
Clobber
Gorefest
Hamstring
Sunburn
Ambush (I know this skill is used by priestresses in act 5 and act 1. It's good for enemies, but as an attack for players it's bad due to the long time it takes to be effective)
Cyclone
Deathstrike (I know this skill used be really strong basic skill of Necromancer before it was replaced. But somehow it got even worse over the years and is rightfully not the base attack anymore)
Guided Chain
OHMAN (way too high mana costs now, that you reduced the mana reg on the mana reg totem and removed that oskill from the ATH rw in boots as well)
Bloodstar
Death Blossom (srsly... Twin fang strike is Death blossom + poison damage. There's no use in Death Blossom anymore)
Pentagram
Pyroclastic Flow (this is only used in TA as far as I know. And it takes too much time to be of use)
Splitfire
Churel
Frostfire Wave (this skill just needs to be available to other classes other than necromancer)
Frozen Soul (it's good as a proc, but has low damage and only targets 1 enemy.)
Shadow Avatar
Winter Avatar
Shock Flower (Even with high skill level, it's still much worse than Twin Fang Strike)
Black Lotus Strike (only the poison part of Twin Fang Strike)
Death Ray (it's not that bad, it just needs a damage tweak)
Orb of Annihilation (same problem as OHMAN. For the Gear that's required it's just not worth it since you can have a better killing speed just playing with totems. Even with the same items. This is a great skill, it just needs a lower mana cost. ~ 5000-6000 should be good.)
Raven Flight
Bloody Mary (I just read the effect of it in the docs, and it seems to suck. Didn't try it out yet)
Summon Avalanche/Bane monster/Daystar (ever since these have been gone as mo's, they are basically useless)
Summon Darklings (I've never like them in Median 2008 since you had to constantly recast them. You might as well remove them since they're so squishy that they're only annoying to use)
Summon fallen
Those add up to 26 free spaces (-orb of annihilation and Frostfire Wave) for new oskills (+- 5 in case someone thinks some of the skills listed are great or want to add something I haven't mentioned.)