Seems you answered your own question.

Just because they are level 3 doesnt mean they are weaker does it?

Also you dont know numbers, so you could've been swamped.

No official competitions,doesn't mean nothing to do, especially for a bully.

Smaller marches or domain guards might be an answer.

That's true about the domain guards.  I have some,  but wish they would give more out in events or make them available to buy in clan store or flat out buy them. Really haven't had much trouble when no events going on,  most just go about their business.  Apparently this guy wants to be the kingdom clown and cause issues for others just going about their business. 

I made an attack with tier 1 troops against a small number of tier VII and tier VIII troops.   The base stats for my well developed tier ones are shown as : offence 1,705;  defence 1,709;  health 1771.  My opponent' tier eight troops are shown as : offence 1746:  defence 1,892;  health 1744.  There are additional bonuses improving offence against particular levels of troops and against troop types.  The bonuses of my tier ones are up to ten times greater.

In the event my tier I troops won the battle and the influence loss on each side (a good measure of outcome) shows my influence loss at 67,586 and my opponent 121,945,344.

There are inumerable ways to improve troops - the improvements on each side are what is significant; tier level alone is of little significance.

The OP is not alone in moaning about tile hits by powerful towns in their kingdom.  I make plenty of tile hits myself and feel comfortable doing so.  I need no reason other than the satisfaction of putting my troops to work.  I also take care to protect my own troops and the OP would do better to put some time and effort into that rather than into moaning.