Bingowings:
We never did see the other Naboo cities, Theed can't be the only one so if there are more leveling one in TPM would give weight to the most flimsy planetary invasion in cinema history.

The cities weren't attacked with great military force because this was a political takeover designed to force Queen Amidala to flee and seek help from the Senate. Sidious/Palpatine didn't intend to destroy it, only do what was necessary to meet his ends. Only Theed was overrun, as far as we know. There was no reason for the Trade Federation to destroy any city.

But yeah, it does look like a non-event, so I understand why you'd want to add more destruction.

Adding human drama to cartoon droids attacking cartoon cities and fighting cartoon aliens would make that film at least slightly human.

Can't argue with that!