Season 12 massively upgraded DPS in key sets or builds, season 13 didn't do anything. Season 14 is going to have double goblins but otherwise will be like seasons 12 and 13.
I think season 11 was when necromancers were brought in, but I might be mistaken.
Basically nowadays it is easy (at least if you know what you're doing) to get into doing GR70-90+ and speed t13 rifts/bounties/farming, which makes it more feasible to build strong characters quickly and get lots of loot. Wise use of the cube and Kadala can be key to speeding this sort of thing up, as well as the use of powerleveling channels for powerleveling, but also boosting of level 70 characters looking to be carried in t13 rifts (or grifts, but this might not be as helpful).
Carrying and powerleveling can occasionally be had even before 24 hrs is up from season start (I always PL some people on the first day for amusement).
In season 13, it took me less than 72 hours to go from level 1 DH on HC to soloing gr84s (I did not have a seasonal cache as I had used it on first day in SC).
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If you can do the CHALLENGE RIFT on first day (after the season officially starts), you get a ton of mats and a good pile of gold. Wait until level 40 or so, then if someone in your party has a tradable custerian wristguard, the whole party can zip to level 50ish by wearing that item (trade it around) when they open the cache, you get xp equal to the gold awarded). Or, if you got one that isn't tradable (gambled for it) you can just do the turn in yourself.
Then craft a weapon and roll for -level requirement, so that you can use a level 60 weapon at a lower level (possibly even 43 or something). If everyone got 50, great - if not, and only one person did, they can carry the rest (my group did that on season 13).
Sometimes the challenge rift is hard, playing with four people can help mitigate this. Sometimes the challenge rift features a character with a Unity, which causes all damage in a party to be shared, which generally causes party dead, very lol.
