Previous session worked very fine, sure we had proxy mercenary leaders on world map, but they are quite obsolete now. This and previous system is very suitable to be on sneakers, so no difference there and nobody is going to make waves out of lagging free proxies because it practically never happened previous session and there are other reasons for it I have explained multiple times.
I played like almost a year on the 3/10 minute timer, never remember any team using waves, maybe some small cells of players used it just like there is some percent now, because there is I know.
World map can be safe, and there can be no annoying Idling timer upon entering the game making it a similar system to the 3/10 minute timer. That will really not change the game play or suddenly players starting to use some mass waves or something.
If only you'd be more experienced in terms of PvP Jovanka, you'd understand what I'm talking about.
And now pretty much everyone uses sandboxie,
so you wouldn't even have to look for any new methods to avoid it.
How does this change anything?

Everyone used sandboxies a long long time ago.
Upon that what I said, you must make an adjustment, that if you have 2 characters with the same IP in game, the second one that connected doesn't drop Idling timer no matter what until the first IP/character is no longer present and it will be fine. (if connected with already present IP address Idling timer is applied, which is working like now already, just need to make in that case for it to also not drop so players can't camp WM on multilogs without proxies.)