IS - Outposts need to have live people defending them.
If we disagree on that basic principle then we'll just have to agree to disagree.
Just because a corp isn't big enough to have people on 24/7, doesn't mean that requirement should be dismissed.
Turrets are a deterrent. They are there so if you have 3 live players online, and a group of 10 bots shows up, you can acutally mount a fairly good defense (lets not digress too far into how/what would be usefull for defense). You may lose some structures and need to zerg a little, but distances are very large, so you'll have a huge advantage.
If an attacker shows up with 30 bots, then they should be able to defeat the automatted defenses, and maybe those 3 players can delay them long enough for help to come, or atleast make them be more careful as they roll over the post. This is where the 'lock-down' timer comes in, so even in these off times you won't totally lose your base.
But, if you have no one online to counter a group of 3 raiders, they should be able to mess with your unattended goodies. But it takes a long time to TF, and its boring. It's also not possible to TF within 50-75m of structures, so if turrets are built in and among your factories, they can't by pass them with TF and will have to neturalize them. Note also, that PBS just got a 2.5 x boost to HP, meaning 2 dps bots and a TF bot are going to spend a lot of time shooting stuff - and if you have rep modules going, they could easily run out of ammo.
tldr- The trade of of being invulnerable with TF @ 1000m to making players spend time and effort to bypass turrets is acceptable.
Note: From a defensive prospective, I would much rather force the attackers to use a TF bot then to simply be able to blow through terrain.