Considering that just over 1000 players reached the final milestone, I'd say that 8 days wasn't too long. If 10-20% of all players got the top milestone, then maybe one could argue that it was too easy to hit. But in this case, the minimum score to be in the top 1000 players was really close to the score for the final milestone.
I thought I might have come up as too "complainy" after reading it, but the post was up already and didn't wanted to edit.
My comment came from the perspective of a player who has now access to several fighters on the 15-20K range. This makes completing the milestones relatively "easy", so my aim was less in that and more in the "Event Rewards" (I really wanted those dia keys). The event been 8 days, I kind of didn't knew if I needed to continue grinding or not to be in the top tier and that was kind of annoying.
If I were to have only 9-12K fighters for this event (my situation like... 2 months ago) I would probably not had aim to the final milestone. BUT I know I would be very gratefull for the time given.
Another way to look into the scores, is that they were relatively similar to the elemental PFs. Spread out in 8 days, I don't know if that's a success. It just means that after reaching the milestone one thought could do, everyone went away to the other PFs (the scores on the light one were actually a lot higher than usual).
But to sum it up, my comment was not intended to be a complaint, just a perspective. The milestones were indeed amazing. The 100M cap was spot from my point of view (in eight days, if you REALLY want to, you can get there). And we are forgetting of the 12 days of givings, which were the most awesome thing, too.
PS: I would really like that fire fighters were more terrifying in defense at least one. For me, something like "Gain enrage when X, and when beneffiting from enrage, blocked hits do the same damage as non blocked hits" would be fun. I don't really have good fire fighters, but they are always so underrated they feel like the Yamchas of the game (making dragon brawler ironic).