Following up on my previous post, I think that if the challenges were unsegmented and if that type of event was only available twice a year, you could add a new feature to these events: taking the level of the player into account for the equipment awarded. That would be a very nice gift for the players that commit to playing the game thoroughly (like me! 😁) rather than rushing it. After all, we are the players that plan on spending the most time with you! 😉
If you have ten equipment pieces as rewards (5 regen and 5 capacity), but the ability to buy them is dependent of the amount of special items harvested during the event (items that you will have spread in the challenges in a way that if you finish only the 1st challenge, you can only buy the lowest regen item and the lowest capacity item; 2nd challenge - 2 lowest of each; and so forth...), then you can change the size of the equipment according to the player's level and their region rather than just their region. You just need to add a factor to multiply the level of the player in the equation.
I made this little table to try and explain my point more clearly. Actual figures are not that important (Pixel can figure that out themselves). The idea is just to see that levels are taken into account.

So let's say you enter the event in China and your level is 270 (true story 😜), here are the ten equipments available:
Regen (per slot): 130 - 146 - 162 - 178 - 194
Capacity (per slot): 810 - 1080 - 1350 - 1620 - 1890
Now, if I only complete the first challenge, I can only buy 130 regen and 810 capacity. Not interesting in China.
If I complete the 5 challenges, I get to buy super nice equipments. But if you're (still) following me in my delirium, you noticed in the previous post that being in China will really only let me access the 162 regen and 1350 capacity, unless I wanna kill myself on the game and push to get the 4th challenge.
So why should I prefer this way?
First, because 162 regen and 1350 capacity is still much more interesting than what is available in segmented events right now, due to the fact that my level is higher now than it was when I started in China.
Second, if I really want to, I can try the fourth challenge and hope to get even better equipments. Or I can keep my extra special items for next year when you'll repost the event and then hit the jackpot!
Does this way encourage stalling in the game?
Maybe, but even if you want to stay in Egypt all the way to level 200 (good luck with that!), these events would only be available twice a year. That's a long wait for only a couple of equipments. Add to that that your capacity and regen in Egypt are quite limited (due to the vast majority of segmented events). So even if you're at level 200 with a couple of very nice equipments, getting through the second challenge would still be, well, a challenge! (That is, if the difficulty of the challenges is well balanced for each region it is aimed at.)
I think that a couple of events with level-oriented equipments each year could really please the more advanced players in NW and Terra. I think it would be a nice way to thank them for sticking with you for so long. And it pleases the OCDs like me who dig every single tile and do every single event you throw at them...😉