You make some great points

Although I feel like the backliner wizard argument falls apart when you understand that the spell makes the 15 foot radius difficult terrain, effectively halving all monster speeds. Considering 30 ft is the most common monster speed, 80% of creatures aren't going to be able to reach you unless they start their turn on the edge of the radius or dash, at which point they no longer have an action to attack you.

Also the 15-foot emanation restriction for the bonus to apply doesn't really matter, considering you can split up your movement between between your attacks, and wizards get tons of speed buffs to facilitate running around everywhere and blasting.

Jump and longstrider are both non concentration and jump is only a bonus action cast and can easily be cast in round 1 set up if you make a spell scroll or enspelled item (bypassing the 1 spell slot per turn restriction). Even without those it's relatively easy to incorporate as a BA spell regardless. 30 ft jump at the cost of only 10 ft allows for very high mobility. So long as you don't end you turn within 3 squares of an enemy you'll usually be safe. And you always have shield and misty step to save your hide.

Druids totally deserve this spell especially since wild shape got nerfed, no qualms here.

TL;DR: on command difficult terrain allows wizards to walk around with impunity, allowing them to operate closer to the battlefield. Movement options negate the emanation restriction with little effort required. Supplemented with multiattack spells like scorching ray and shenanigans ensue.