Now I'm not asking for much, just two small changes that I would love [Command: Attack] to have.
For me, a good Summoner Class design is how commanding the summon adds to your APM, like an extension of your moveset instead of just a NPC party member that takes damage and does stuff on screen.

Since this is the only skill that actually allows that playstyle, I tend to use [Command: Attack] to send Heilang first as Im rushing down a crowd of enemies. It does some decent burst damage at the start of every combo and it'd be a decent grinding tool if not for the two cons of the skill.

One, the way your Tamer has to stop and actually has casting time for a simple skill feels VERY clunky.
Two, If certain skills are used while Heilang is running towards the target, his attack gets interrupted and won't deal damage.

So my suggestions are simple:

Allow the use of [Command: Attack] while running/moving 
Allow Heilang to prioritize [Command: Attack] over any other action.