Sure, it's a good idea.
Let's see.
1. trumpet:
Hail and Fire. Pretty straightforward: ice and fire damage.
Destroys plants.
2. trumpet:
Destroying the oceans. Not sure on that one.
3. trumpet:
Poisons rivers and springs. Also not sure. Can create diseases?
4. trumpet:
Darkens the sky: darkness effects.
5. trumpet:
Insect swarms.
6. trumpet:
Summons an army
7. trumpet:
War and judgement. Difficult to implement.
Overall opinion: very blasty. I'd prefer if at least some of the trumpets had more of a connection with heraldry and messages than killing people and despoiling the land. Actually, all of that seems a bit much wanton destruction for the forces of lawful good.
Perhaps just a few blasty trumpet archons?
Herald Archon: calls forth the armies of Heaven. Summoner.
Thunder Archon: calls forth darkness in the skies, lets fire and ice rain down.
Sounds better to me.