Base defense and intercepting

[FireStorm20]

The base defense is a really cool feature and it ties in nicely with base building , planing. However on my latest very hard game i noticed it doesnt really pay off to allow for the enemy forces to attack it. Instead of having advantage on your home turf , with your turrets, it seem like 10 x times harder then intercpeting an assualt fleet and just ducking it out before they reach the base. On base assualt, first and foremost the enemy deplys mechs and ultimate behemoths, the whole deal of a 5 level city. It doesnt if you intercept the fleet.
Second the turrets dont attack at all the enmy mechs. Third it seems to have much more units then in a battle when you intercept the assault fleet.

I think you should somwhow be forced to defend the base from time to time or at least it should really be advantagous with proper turrets build up. At the moment late in the game its close to suicide , compared to the relatelviely easy interception battles.