Does "killing the city" mean down to 0%, or something less?
To get the maximum effect of 150 minutes, yes. But every city tile detstroyed counts.
As a matter of fact, the City is
very important now. Not only because the standard downtime of towns has been cut by 1/3rd down to 30 minutes, but because the town buildings can now be resupplied. And it takes only 3 loads of cargo to bring it back up if the City had not been hit.
I guess the news isn't out yet. Just spent a few hours trying to intercept inbound buffs at altitude, most just bailed or went in to fields at 10k.
It will take time for the changes to really get known to and understood by the people. We had years of "the strats ain't worth it" and basically nobody cared about them. And now there is this big change, but only a small note on FB and in the News & Announcements section. And not even an explanation, one would have to figure out the changes from the help section on the website. I' am curious how long it will really take for the populace to fully recognice the importance of the mechanism I described above. 7 years in AH land made me a pessimist in that regard...
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And there is one issue I still have. Well, not really an issue, possibly more of an personal preference. But I really do not like the new .dt command much. Yes, it's a great tool at first look, but I'm not very fond of that huge reduction of fog of war. "Is the town down?" "Was that CV X? that I just hit"? "How long until hangars pop?"
Players knowing that the town or the VH will be back up in exactly 1.4 minutes may take out some exiting moments, IMHO.