I'm thankful for their new design, actually. After many years of trying, I have now managed to successfully kick my Reddit habit completely and have gained precious hours in my day.
I've been trying to pin down _why_ I've had the same reaction as you, but I really can't put my finger on it. Something about the new site just somehow puts me off. While I could mindlessly browse the old site endlessly, something about the new actively makes me want to close the tab. Either way, a good thing.
2. Everything is clickable. On a crappy touch pad I misclick so much stuff.
3. Resource usage. I bought a lighter laptop. It sacred me actually because embedded YouTube was lagging on the new site. This was even worse because everything is ckickable problem.
4. It took a lot of clicks to see a content. There might be an expand / collapse but I had a hard time finding it consistently.