He also explained why shit lags, and it's not really the engine but gameplay decisions like rolling for hits/misses on every single projectiles when you're throwing like 40 on the screen, all of which then have to recalculate a target if it hits for chain purposes, while also applying varying amount of debuffs and so on. Plus mob density in poe feels higher than many other games. You only get high density in D3 by wrangling a couple of screens together, and then there's like way less calculations going on because way less little bits of things. Even then back in the days the game would fucking die with certain items and certain specs, I think they kinda fixed that over time but I remember people massively complaining about high GRs lagging like shit because stuff wasn't dying fast enough and you'd just spam skills on like 30monsters.
Also shit like cannot die and proximity shield completely fucking kill performance because the calculations keep being done for everything over and over while shit isn't dying.
They could probably clear up some of the performance issues removing or simplifying mechanics, but then you'd run into issues with ppl complaining because it's not as fun anymore. Shit like cast on crit/PP have already been nerfed because of that.
For the recruitment iirc it has to do with NZ laws. They have to recruit NZ ppl in priority and can only recruit foreigners if they didn't find someone for the post for x amount of time or already have y amount of NZ people for similar posts or some shit, I think I remember one of the devs explaining that on reddit.
Anyway Blight the way it was designed was probably a poor idea. Generally TDs have way less mobs, and it's more about strategizing your towers and stuff, but they probably didn't want to go full TD cause ppl would have said it's boring, but the way they do it is just fucking stupid and I don't know why they thought it'd work well that way. More importantly, it has to have been apparent pretty early on that the mechanic was fucked, I don't know why they decided to keep going with it. It needed to be put on hold or tested further, the current implementation was just terrible at launch and some issues should have been obvious with minimal testing(map has nemesis mod, portals vomit nemesis rares spamming fucking lightning storms and crashing the instance for example). And Blight Maps are a joke of a concept, it's like they didn't even run a single one. It was apparent literally in the first day that the concept was flawed and that they needed to spawn way less shit. How did this make it past QA? People were crashing the servers, not even their PCs which yeah sometimes you can't test for all types of systems and shit but that was their own servers crashing, surely that should have happened in testing too.
Honestly they should go back to a longer cycle and just have "easy" 1month leagues inbetween shit, flashback or better mayhem(voided). Yes they kill the temp leagues, but what difference does it make there's a temp league that last 3months or a temp league that lasts 4months but 1month is dead. Shit just turn off the temp league if that's a problem, same thing really.