Be careful with bonus armor on Battle Meditation. When attack bonus and Armor Class are so narrowly restricted (the best a typical character will expect without magic items is +9 to attack rolls, while the best AC without magic is 21 if you get the Defender fighting style), +2 accounts for a lot. Essentially that represents a +10% boost to the highest armor character without armor, or a 1st level spell slot (Shield of Faith) which normally requires concentration to maintain, but on every party member within 30 feet of you. Formation Tactics is more reasonably balanced because its duration is very short and it requires your class resource.
I feel like Channel (Unity Strategy) is pretty strong. Maybe make it once per short rest or long rest? Alternately, make it require Battle Meditation. Just from an eyeball perspective though, I guess your ally is still spending all of those resources so in the "day resources" you still come out even.
For Combat Inspiration, maybe make it work like Bardic Inspiration dice instead of Inspiration, or require it be used before the end of their next turn, or make it a reaction whenever an ally makes an ability check, saving throw, or attack roll that only applies to that check. Otherwise Strategists are just going to give everyone in the party Inspiration, start a short rest, and everyone will have Inspiration.
United Front is either quite strong (given Strategist's bonus to initiative rolls), or quite weak (in games where dungeon masters already use group initiative). Maybe make it one ally? Or once per long rest, you choose another ally to take an extra turn right after your turn?
I love the class overall, I also tried to bring intelligence more into the spotlight (though I made a spellcaster). I marked in orange things which I think should be changed because they are too strong, and in blue things which I wanted to say something but wouldn't cry foul if they were left in.
Related non-mechanics: 5e doesn't much use the free action terminology. Generally it is described with "as part of X action" or "on your turn". Everything else is either bonus action, action, or reaction. Also, once per day is typically written as "once per long rest" or, "you regain all uses of this ability on a long rest".
EDIT: Look at my Runecaster and tell me what you think?