Wild exaggerations aren't helping your cause. Are you looking for sympathy or for broad, sweeping nerfs that'd change the feel of D2 completely? Maybe your problem is that you're playing a melee character in hell--which has never been reliable in retail d2, during any patch.
I can do the three inferno portals on a shield throw barb with IK set and a raven frost, and reliably never die. I can kill mappo, sha, and kaalut on a trap assassin wearing nat's and reliably never die. I can do LK on my necro still in trangs and reliably never die. Smite has always had a niche in D2 ever since it became popular when Ubers became a thing: standing toe-to-toe with high-end bosses and dying less often than most other classes.
Should mobs like Cathulhu and Belial be so hard as to make most characters have to try a few times to kill them? I think so, yes. Does smite do better against those two bosses than most other classes/builds? Yes. Smite has a niche. Use it for that. Not for cow games. That's D2 common sense.