I would like to see some strategic (non combat) spells.
Such effects could include teleportation or the summoning of independent allied parties.
Ritual of town portal: The players party is teleported next to a nearby town. At low levels, the chosen town could be random, while higher levels could allow you to be more specific and increase range. The cost of the ritual could scale with the size of the players party, making moving whole armies this way less than efficient. Such could be used to escape an approaching enemy lord, return to town for supplies, or simply to speed up a journey.
Upon building a landing portal in an owned castle or town, you should be able to select your fief as a teleportation destination, actually arriving within it's walls. A dangerous gambit, considering you would have no idea of the size of an invading force.
As for party summoning, such should be self explanatory. The player uses a ritual to create a party of undead units, then sends them on their way to attack smaller parties. As undead need to be controlled, the cost of the ritual could include a relay amulet of sorts, in short, a means to control the party remotely. Such extended control over the undead could come naturally to a lich, extending their ability to threaten the land.
The size and number of summoned parties could be limited by the necromancy skill. By default, when summoned, they patrol an area around the summoning point. That point is their HOME location. Alternatively, they could be ordered to accompany the player. This would allow a player to amass quite the horde of expendable minions. When the player is done with them, they can either dispel them, freeing up a party slot, or order them to patrol their HOME area.