The WD sort of fails to deliver on that. Even if the WD had tons of summons, I really like the Dungeons and Dragons style feel of a true Necromancer.
I imagine a few types of summons:
1. Dumb AI fodder type summons, walk around, attack things
2. Smarter summons, incorporates better skills and uses them smarter
3. Awesome summons, great skills and use them very well
Different flavors of each kind.
Obviously you have more of 1 than 2 than 3 and your character basically has spells to manage and support the horde.
1. All summons attack this area
2. All summons form a blockade here
3. Do your thing
4. etc or more ideas.
1. Heal all summons within 6 yards of casting location
2. Boost the dmge of fodder summons for 3 seconds
3. All summons within 6 yards of an awesome summon become immune to control impairing effects for 10 seconds
4. etc or more ideas