Make summoning passive and not require corpses or a skill slot.
Skeleton warriors automatically and passively get summoned every 1 second, doesnt require a corpse. (Add legendary effect that summons 2 skeletons every 1 sec that works on both warriors and mages)
Skeleton mages get summoned every 2 seconds on a seperate timer, doesnt require a corpse.
Skeleton priest effect happens automatically every 5 seconds and consumes a corpse, if no corpse is available it sacrifices a skeleton warrior, requires slotting the skill. (Add legendary effect that turns it into a passive aura that ticks every 1 second as a flat heal. Minions could still die if swarmed but would be significantly more durable when combined with minion passives)
Summon golem skill is passive and automatically summons with the current cooldown. Using the skill on your bar allows access to the golems special attack, if not using it the golem is limited to its basic attacks.
Turn the summon skeleton skill into a command/mark skill, allowing necromancers to use it on an enemy to force all minions to attack it. Skeleton warriors and the golem instantly charge at it through any enemies in the way, skeleton mages teleport to outside melee range but close enough to be inside suppressor bubbles.
Can also be used as a move skill to reposition minions.
Or players can choose not to use it and let minions do their own thing to free up a skill slot.
Add an option on the skeleton warrior page to choose an additional damage element, for example “Skeletons deal a part of their damage as shadow” or something like that.
Doing it this way means a necromancer can fully customise their skill slots while still having access to their basic class mechanic or focus more on summons and gain access to their additional functions by sacrificing skill slots.
And as a seperate suggestion/wish:
Add an equipment window for skeletons to allow us to add equipment to minions even if just for visual customisation.
But would be nice to equip certain gear on minions to focus the type of attacks they do, focusing on crit, damage over time, vulnerable damage, shadow etc. So for example if you’re focused on shadow damage over time your minions could be geared to align with that.
Those are my suggestions, not that I think anyone at blizzard would see but still.