How in Gods name are so many people struggling with the game?! I made the whole campaign in Tier 2 from the beginning, died at most 10 times. Had by level 35 full gear with legendaries that suited my build and had to buy an extra storage to store the rest of them cause the default one was already full. By lvl 50 I did the angular dungeon and switched to Tier 3 just to keep blasting through everything like its nothing. Im hoping Tier 4 its at least something of a challenge. Im running a Blizzard/Hydra Sorceress build which I developed from scratch by myself while I was leveling through trial and error and using common sense. Even with only rare gear I can keep going, as in T3 most of the sacred rares outperform the normal legendaries.
And of course there are “bad builds”, the important thing is there are no bad skills, and I think D4 does a great job in that regard. Have now to test Barb and Necro, but from what I have seen on the rest of chars they are pretty well designed in regards of every skill being usefull.
The key is to combine the skills in a usefull way to get a viable build. As an example, if you get only passives and no active skills, u cant expect to do that well as u will be lacking tools to deal damage and utility to survive. You dont even have to put all-in in a specific direction, which surprised me. First I was going full ice sorceress, with all ice skills there are, which was working fine. Then I began experimenting with mixed builds and ended with my Blizzard/Hydra build which is a blast to play for me. No Ice Orb, no ice shards, no teleport.