wand vs scepter.

Yeah i'm fully aware it doesn't effect EK.

I just have it for the +mana and spell damage.

Yea I'm using a sceptre too for my EK guy right now because it has some spell damage, some resists, and some cast speed. Also it allows me to use leap slam; less finicky than lightning warp and less likely to desync than whirling blades with daggers/claws. Also the Hatred Aura and Added Fire Damage benefits from this. At least on my Bear Traps that increased elemental damage is a pretty significant DPS boost against single targets.

I also wanted to add wands at the highest level will have up to +20% spell damage implicit mods whereas sceptres only have the +20% elemental damage implicit mod at the level 60 sceptre (Opal Sceptre). However Opal Sceptres will always be +20% elemental damage while the Prophecy Wand or Opal Wand will vary between +16/17-20%. Sceptres can have all the spell related explicit mods (spell damage, spell crit, cast speed) that the wands can have but sceptres are the only weapons to be able to reach the highest elemental damage mods (+27-30%). So if you're a mage focusing only on one element like cold a perfectly rolled sceptre would be better than a perfectly rolled sceptre since spell damage increases and elemental damage increases are the same on say Freezing Pulse. But if you need to use skills like Power Siphon then obviously wands are the only choice. With wands your only choices of escape are Quicksilver Flasks and Lightning Warp. They work together but it's not really reliable in that there's still a delay until you start traveling. Sometimes this may be preferable because you can still cast spells before you teleport but that delay might kill you if you're careless. On the other hand sceptres gives you another option, Leap Slam. It's a great little ability that has less of a chance than Whirling Blades with daggers to desync and it's more reliable than Lightning Warp. The downside is it's pretty slow and can only be improved with increased attack speed. You can attach a Faster Attacks support on it but that's another gemslot you have to worry about. This brings up another good option for weapons. Daggers are really good for caster builds that focus on crit because they offer a really good globabl crit chance for their implicit mods. The problem is they don't offer any cast speed mods so if you need that you're outta luck with daggers.