Wizard's Invisibility Spell
Footsteps should be silent or at least muffled. It's such a short lived spell lasting only 4 seconds, and the afterimage gives you away well enough. Would be sick to make some nice melee plays in solo, at least 1 good hit on the enemy before they appropriately react.
Also, solo wizards struggle a lot with classes like ranger or bard hiding behind and circling pillars. Extremely hard to win that kind of fight... Warlock and Sorc at least have some ways to deal with that. If Wizards had silent invis, they could get a decent flank on them, and catch them slightly off guard.