First off I'd like to say I'm super excited for a full summoner class as I've run summoner characters both in vanila version and synergies for a while now and would like to point out the problems pets/summons encounter both in regular gameplay as well as boss fights and environments like or'ak basin/pass/darkness falls.
1:Melee based minions deal low damage or no damage to higher tier monster(heroes/champions/especialy boses),this is because moreso in synergies than vanila game the monsters have a great deal of atraction toward atacking the player and this leads to a need for kiting which means the player runs around boss/champion runs after the player and the melee pets run after that and barely ever land hits.To adress this I think a full summoning class should have a strong spell to imobilise 1 target or a small group in a targeted location.
2:Minion survival:The master minion buff spells I found to be a welcomed boost for all minions within the necromancer class however with the scaling of difficulty(dakness falls) those buffs either help very little or the enemy mobs debuffs render them obsolete.
3:Weakening the enemy:Armor shreding or specific elemental armor debuffs I feel would be a must since all the minions we curently have access to run into issues dealing damage even with high % of pet/minion damage amounts from gear/gems.As an example to this i ran a mix of dreadful incognito(8piece) along with 4 piece reactive aftermath (both rings(240%) dual melee with 4x150% pet dmg gems) through darkness falls and noticed the minion damage to be quite low.
4:Target primary:I'm not sure if this is even possible through modding but giving the minions a way to prioritise their targets would be extremely helpful.