Does anyone use the wall (dragon ability)?
 

I normally just ignore the dragon's wall ability and have never upgrade or chose this ability.

Am I missing out on using it or should I continue to ignore this ability?

The wall is very useful in limiting the enemy units' moveability. It is also very useful in protecting a number of weak ranged units if it is maxed and the enemy has no ranged units to inflict any damage on them.

i used it hell a lot in hardest mage part of game (rusty,verona)