[Skarg]

I would say dragonets, like anything that can't attack in melee, don't engage.

If they are unable to attack due to movement, have them Dodge/Defend, making physical attacks on them 4 dice versus DX -4 (-8 for ranged), and have them end MA several hexes from a wizard if they figure out wizards can get them with Thrown spells. When moving first, there may be other things they can do as well to keep out of range of melee attacks and/or behind walls from other attacks, or just fly high enough over their foes that they can't be swung at, and ranged attacks also have a height penalty, but they can swoop in as soon as they do win initiative.

That way, yeah they could be frustrated by not being able to end movement on a victim, for a few turns, but they can probably make their foes look even more fooling trying and failing to attack them, breaking arrows on walls and using up wizard ST.

If the initiative situation is nevertheless really galling you, it seems to me that since they are DX 14, flying MA 14 and this is their specialized tactic, that one might want to house rule that:

Dragonets effectively have Tactics talent (limited to their own way of fighting - no Henry, you can't make your dragonet familiar be your party leader).

and/or

A Dragonet can fly straight into your hex, which both engages you, and means than if you shift away as your movement, the dragonet moves with you unless you have higher DX or higher MA than it does.