That’s the crux of this.
1 to 50, you can play through the campaign.
50 to 70 you can do the Capstones, World Bosses, Legion Events, and finalize your builds by getting leggos and Uniques in NMDs, Helltide and Whispers. It feels as if the end game is really the level 50 to 70 range. By level 70, you’re mostly set.
70 to 100, there’s nothing new to do except Uber Lillith near 100, and get incremental stat upgrades for you gear and paragon board. But it’s all done through the same content you spent level 50 to 70 grinding out, so it’s already causing burnout. Leveling up past 70 is also a grindy treadmill. Exp gain is slower. It’s just a slog.
Blizzard needs to spice up level 70 to 100. Add new content we haven’t already done. Double the EXP rewards. Add new, attainable, items (Not crazy rare Uber Uniques that hardly anyone will get.) But beyond that, we need new things to DO. I’m personally tired of NMDs, Helltides and Whispers.
Add more World Bosses. Add new dungeons that aren’t just copy-and-paste of the current ones. Add Raid dungeons for larger groups of up to 12 players. Add large-scale PvP, like 6 v 6 team battlegounds. We definitely need more Group content for those last 30 levels. And more Group-making option in general to go along with it.