At the moment, there's set to be a Reflection tribal in (Foggy Mirror, Sharp-Edged Cord) so that +1/+1 buff in those cases is indeed intended. The original concept of this card cost and created 0/0 Spirit creature tokens with flying. Given how well it will play with reflection/shimmer cards in general, I decided to increase the cost by even if the tokens lost flying in transition. Flavor may need an update as well...
These UEOT effects confuse me a bit. Would it be any different if it said
> "Creatures you control have base power and toughness 1/1 this turn.
Ie. How would you actually word the effect that's essentially Humility / Godhead of Awe is in effect for creatures you control this turn - regardless of when they are / were on the battlefield?
Like, with UEOT only affecting creatures that are on the battlefield when it resolved, it makes me think that Glorious Anthem should only affect the creatures that were on the battlefield when the enchantment entered the battlefield. Is this all about the mess that's layers?
As for rarity, it's certainly complex (it was originally intended for "Future Sight 2" set), but I don't think it has any of that 'oomph' to make it rare. You can't really even stop creatures with evasion with this card. There are slots free for white rares, but this was included exactly to spice up limited because of the Reflection tribal and sac outlets and death triggers (Inhuman Skinner, Reveler in Chaos, Ravenous Lastborn, Godhead of Obfuscation).
Neat. I find it kind of funny that 0/0s will get a +1/+1 boost (Phantom Nomad for example.) But that's not a big boost, and an uncommon event, so no problem there.
I'm going to make a presumption that this card isn't broken, since in most situations it's 3 target attacking creatures are blocked and/or Rain of Bladesed. Though, admittedly, that's a lot of sacrifice fodder. Ah well. It could have been a Raise the Alarm. True.
The guess the real question is whether or not this card could be printed as uncommon. Because p/t setting requires specialized knowledge, and as SecretInfiltrator pointed out, even experienced players fail the test sometimes. But, you know, different people have different tolerances for the rarity-complexity equation.
Second ability was:
> If ~ would be sacrificed, you may remove a +1/+1 counter from it instead.
Was:
> "Whenever ~ fights or becomes blocked, it gets +2/+2 until end of turn."
"... or enchantment..."
Forgot to add that
to that mana cost
Probably doesn't work with Flesh Golem so one or the other needs to modified in some manner.
EDIT: Flesh Golem has now been updated to work with this.
had wrong artist credit
At the moment, there's set to be a Reflection tribal in
(Foggy Mirror, Sharp-Edged Cord) so that +1/+1 buff in those cases is indeed intended. The original concept of this card cost 
and created 0/0 Spirit creature tokens with flying. Given how well it will play with reflection/shimmer cards in general, I decided to increase the cost by 
even if the tokens lost flying in transition. Flavor may need an update as well...
These UEOT effects confuse me a bit. Would it be any different if it said
> "Creatures you control have base power and toughness 1/1 this turn.
Ie. How would you actually word the effect that's essentially Humility / Godhead of Awe is in effect for creatures you control this turn - regardless of when they are / were on the battlefield?
Like, with UEOT only affecting creatures that are on the battlefield when it resolved, it makes me think that Glorious Anthem should only affect the creatures that were on the battlefield when the enchantment entered the battlefield. Is this all about the mess that's layers?
As for rarity, it's certainly complex (it was originally intended for "Future Sight 2" set), but I don't think it has any of that 'oomph' to make it rare. You can't really even stop creatures with evasion with this card. There are slots free for white rares, but this was included exactly to spice up limited because of the Reflection tribal and
sac outlets and death triggers (Inhuman Skinner, Reveler in Chaos, Ravenous Lastborn, Godhead of Obfuscation).
switched the order of effects and removed the reminder text
Neat. I find it kind of funny that 0/0s will get a +1/+1 boost (Phantom Nomad for example.) But that's not a big boost, and an uncommon event, so no problem there.
I'm going to make a presumption that this card isn't broken, since in most situations it's 3 target attacking creatures are blocked and/or Rain of Bladesed. Though, admittedly, that's a lot of sacrifice fodder. Ah well. It could have been a Raise the Alarm. True.
The guess the real question is whether or not this card could be printed as uncommon. Because p/t setting requires specialized knowledge, and as SecretInfiltrator pointed out, even experienced players fail the test sometimes. But, you know, different people have different tolerances for the rarity-complexity equation.
You might want to swap those two abilities. The first ability only affects creatures already on the battlefield as the ability is resolved.
+
to mana cost
reactivated
flavor text edit
"exiles two" -> "discards two"
flavor text edit
deactivated
deactivated
First ability was:
> You may exchange control of two target permanents with converted mana cost 2 or less.
"his or her" -> "their"