Spell Balance Question/Idea

So what's the word on spells that block off an area or create walls or somesuch?

I've been working on a Wood Elf warband for a while (who hasn't?) and I was wondering if there's any precedent for a magic spell that blocks movement. This seems like a really interesting ability and would work very well for a warband what likes to shoot people.

I'm thinking either a spell that acts as a wall, either completely blocking a route off or requiring a strength test or something to pass.

How fair is it to completely block passage, as a summoned wall of trees might?

How about a tangled mass of brambles that requires a strength test to pass through? Or perhaps an initiative test?

Or a wall of haunted trees that attack models attempting to pass through and halts movement of any model they manage to hit/wound?

The closest that comes to mind for me is Tanglefoot, from the Prayers of Taal list in the Ostlander warband. That one halves movement within 12" of the caster for one round.

The Prayers of Taal list wouldn't be a bad inspiration / balance check for some Wood Elf spells.

There are also some single-target movement-affecting spells:
- Amazon Rituals: Singing Wind
- Charms & Hexes: Dust of the Blind
- Shadow Warrior Magic: Shadowbind

Completely blocking movement for more than one turn sounds pretty rough to me - Tanglefoot can be pretty rough as it is. Perhaps in a forested setting, I could see a Wall of Vines for one round - make it a 3" wide wall up to 16" away, with a Strength test required to move through normally. However, the wall would be a complete obstruction, blocking LOS and (of course) shooting.

That's about what I had in mind! Lasts until your next turn, of course.

I'll check out those spells you mentioned, too.