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.