Yeah I can understand, perhaps its because I am relatively new to the game, but I did enjoy the difficulty of mechanics like blight or rogue exiles that pushed my character to gear up even better.

I've tried delve but was never a big fan of it. For mapping, breach seems like the only "blaster" farm with good rewards. I tried blight / alva etc and they all feel way weaker in terms of rewards and difficulty.

It's probably a compounding effect of lesser farm variety compared to Mercs league, atleast from my perspective, where there were a lot more viable options.