It's only "busy work" if you're approaching it from a "completionist" mindset/standpoint. Literally all of the stuff you claim you had to do was entirely optional, sans maybe the lab trial (which are fucking awful and need to change, I agree). There's nothing preventing you from rushing to the boss, killing him, and moving on to the next map. Hell, in many ways, that's actually the most currency efficient way to do it.
In terms of bosses/rares seemingly taking longer to kill, that's mostly a product of your build. There's some builds that have a very high floor but their ceiling is relatively low - these are mostly the builds that people consider "starter" builds. Great at the beginning to get some initial currency and farming in, but a lot of them start to peter out toward higher tier maps/bosses. Then there are builds which take fucking forever to ramp up because of gear requirements but are absolute monsters once you've gathered all the necessary items. These are those builds that you'd see move Shaper phases in 2-3 seconds.
Now, with that said, it's very obvious they've ramped up a lot of bosses and rares across the board. However, players have been scaling for months/years without any of these values being touched. So, we were at a point where player power had gotten so insane that you were able to mostly just flat out ignore boss mechanics (Shaper is a great example of this). Whether or not you think that's a good thing is up for you to decide. Personally, I'm a fan of the increased difficulty, but I really think GGG needs to implement either a combat log or at least some sort of death "recap" situation where you can see exactly what mechanic did you in.
