If you want a Necromancer then there is an Occultist class inside the second version of Darkthan Classes. This mod is a finished class pack of 6 classes and is very well polished.
The 'Witch-Doctor' is a specialized summoner that also has access to melee skills. This 'Prime Summoner' has skills of a beast master theme: The 'Theolentist' can be more powerful than vanilla however it has awesome access to various summons and can go with a pure summon build. The Bot summons have been edited to deal electric damage and they do benefit from the electric passive power boosts. The 'Electrical Engineer' is powerful for vanilla however the bot summons have been increased from one to three (I forgot if this can be gained at early or max level).
The 'Tenebris' class is more powerful than vanilla and is not a specialized summoner however it can rely heavily on them. A general rule would be that a Class must have more than 3 Summon Skills and ideally at least 1 Summon Skill that has more than one entity.
