Magic Warlock: Where should remaining skillpoints go?

Most importantly, get at least 1 pt in

Consume and

Bind Demon.

With only random +skill from gear thrown in, that should get

Demonic Mastery high enough for 2 demons and should get

Consume high enough to

Cap out the defiler bonus (-10/+20). The 1st of those demons is your defiler

Consume. The 2nd your bound demon.

IF you want to

Consume your bound demon as well, you may want to keep lvling

Consume as those can require higher lvls to max out the bonus. Though considering that re-binding the worthwhile ones every single game takes more time than consuming them will ever save, I for one wouldn't do that, despite some of them being crazy good as a

Consume bonus.

If you really want a 3rd demon (

Consume + bound + 1 summoned or 2 consumed + bound) then put enough pts in

Demonic Mastery to hit lvl 20 with gear.

As Chaos, sigils should get max range even as 1pt wonders so little (if any) point in putting more points into those. Or just get the one you want off your weapon with a proper base and you're set.

Levitation Mastery makes for a good 1pt throwaway, just to save a handful of stat points on your weapon reqs.

And then you're still sitting on quite a few points left that certainly aren't needed anywhere anymore. Using those to level up

Bind Demon is one decent option as it not only improves said demon's damage and whatnot but it also gives you more options in demons/makes your target easier to grab as bind itself will add the more critical pieces (at lvl 20+, every bound demon gets extra strong, extra fast, spectral hit and most importantly aura enchanted so you don't need to have those on the demon to start with).

Psychic Ward would generally be an option I suppose but the absorb ends up so low that it doesn't really seem worth it.

Blade Warp is a solid 1pt wonder as well to help with travel time, if you don't have Enigma.

And if you're so inclined, hex: siphon does seem to work with spell kills as well to get you some free regen.
(Don't think the other hexes do although I haven't actually tested those in that regard)