Well don't forget, not only won't you be able to elite both units without spending cores, you won't be able to do any of the event exchange shop trades that are worth doing either.
Regarding pumpkins: I haven't been hitting the regular map too terribly hard during the event, to the point where I wasn't even scouting for oil much until recently. That all changed once I looked at the pumpkin total. I'm closing in on 20K pumpkins, so they're going to be a bigger factor than we initially expected. If you do mid-level tiles while you're waiting for your casualties from the event map to repair you can bring in a lot.
But yeah, this is still going to suck for those who don't have time to play every 2-3 hours...I've even resorted to no-lifing it with timers to wake me up when repairs will be complete, and that's not going to be for everyone.
This event made me give up the game all together its obviously created for the veterans who have started from the beginning, for those that started later the units are too weak to make any reasonable gain turning it in a massive grind without being able to even get the event tanks,
The fact that we're required to spend cores just to get all the copies of the event unit kills the purpose of an event for me. It doesn't help that even then, that's only half of the rewards, the other half is in the event shop, which most players don't even have a chance to get as their resources will go towards trying to get the event unit and some items require even more cores.