The Go Go Go! Level 1 Quest Reward has been updated to include the manual control you are speaking of. Having the control over the units to follow you or attack specific target (potentially enemy heroes) makes the Barracks build much more threatening, increasing the instinctive to find the Barracks and destroy them. See the Go Go Go! talent description for details.

Short answer yes. Daxton has little to no team fight presence and therefore relies on minions to do the damage for him. If you make it to level 20 and grab all the talents and the enemy team has not destroyed your Barracks several times over, then they will be in a world of hurt. Remember that if a enemy Hero destroys one of Daxton's Barracks, he has to gather more minerals to replace it. Keep in mind, that Daxton's minions are much more squishy than the normal map minions. Take a look at...