I think most people would agree a mechanic is needed so people can't avoid attacks, but the main problems with the current PBT are that it's cumulative and it kicks you repeatedly. Even very casual players are finding themselves repeatedly kicked from the game. Also, the automatic village guard does nothing for me except cost 15 minutes more worth of collector loot after each successive failed attack.
Before the patch you were given 6 hours and booted for about 10 or 15 minutes and it wasn't cumulative. It reset to 6 hours anytime you put it down more than 15 minutes. I concede this might not have been enough as a good base might often go 15 minutes without being attacked.
The way to stop people from staying on 24/7 is use the old system, but also count the OFFLINE time cumulatively. If someone doesn't stay logged off enough over a certain interval, then kick them for an extended period.
It would look something like:
20 minute break forced every 6 hours.
If (offline time < 90 minutes over past 18 hours) 1 hour break forced
This example has them offline for nearly the same time as the current system and for even longer periods. It allows players to put in long sessions and ensures they stay offline for extended periods at least once a day. Figure it needs to be a good chunk of a day to focus more on exploiters rather than people enjoying long sessions.



