No. There's only a small handful of associations that can even come close to handling many of the bases belonging to the top legions. I suspect just about every legion on the leaderboard has at least a level 5 base. Also, the only ones "bragging" are Valocis of Home One and BlackKnightmare of Anomaly. Home One is 39/37 and Anomaly isn't even on the leaderboard.

Guarding a base should do no more then allow you to see the list of top 20 attackers and allow you to target them. You should only be able to guard a base if it is under attack.

If you are in a space battle and the enemy ships are attacking your base you are generally applying no bonus to your base by being there other then to target and disable ships attacking it.
The attackers would of course be able to share defenders ships with their legion to take it down if it is becoming a nuisance.

This allows for defenders to actually feel like they're doing something instead of just activating abilities and waiting without harming the attackers TOO much, especially if it is a multi legion effort to take the base down.

If further balance is needed, an added bit could be that if you have applied any base abilities you must wait 15 minutes before you can guard your base. The idea here is that if you are in the base activating abilities your ship is docked and you must get to it, start it up, and get free of the base before you can engage in a defensive role against the attackers.