A fatal flaw I an seeing in day two is that for new players this event will be over in 4-5 boss kills. They won't have the IPH to buy any extra units so they are dead in the water for the remaing number of days since boss level does not reset.
I don't think dev really thought this through very well again! Yeah go figure..... I'm guessing when my main guy hits boss 34 which will be in the next hour it's dead as well since it looks like they did not change that portion of the event. Buying disposable units is pointless to a degree unless these units allow you to exceed the 3,000 unit limit. Sorry nobody has mentioned this one way or another but if they don't stack beyond the 3,000 this is unbelievably stupid.
In terms of grouping players, not sure what the formula is but my L8-10's appear to be grouped with L 100+ so they don't stand a hope in hell of advancing further, er well I guess that is rather irrelevent if they can't kill anything I suppose.
Yes seems like an interesting twist, sadly poorly executed and thought out though.