"ladder-like" system is on the way for Diablo III. They're calling it Seasons and it's still being worked on. There will also be "more legendary items" as rewards for Seasons and tiered Rifts.
That's the other thing coming with the "first big content patch" for Reaper of Souls. These provide "increasingly hard Rifts," to see who can go the furthest.
Blizzard would rather spend time creating new legendary items than going back and retrofitting old ones with new affixes etc. They tease new ones with all-new effects.
Blizzard reiterates that Seasons and tiered Rifts are due out with the first major content patch for Reaper of Souls, and not just your standard patch. Tiered Rifts are designed to provide a competitive leaderboard for the new Adventure Mode, which lets your travel anywhere with no story restrictions.
The following was announced by Blizzard's Josh Mosqueira:
Seasons And Ladder-Like System
One of the features you guys have asked about a lot, that we have done a lot of research for, is something called ladders. I'm happy to say that as part of our first big content patch in a couple of months, we will be releasing Seasons, which will include a ladder-like aspect to them. We're still working on them, but the general gist is that you'll level up a new character, we'll have specific ladders for Seasons, and also some goodies that will drop along the way. There's more information of that to come, and we're not making an announcement of when, but that's coming in the first major content patch - not the first patch, but the first major content patch.
There will be more legendary items in the future, both for rewards of Ladders, and also rewards from the Tiered Rifts. For the current ones, we probably are not going to revisit them. They all take time to do and I'd rather we were adding new legendary items, and the time is better spent on new legendary items than going back to refit old ones.
Tiered Rifts And Leaderboards
There is another major feature in the patch 2.1, which is going to be what we're internally calling tiered Rifts. The idea is a challenge scenario, where players do increasingly hard Rifts, to see who can get the farthest. You do your bounties, you do a Nephalem Rift. If you clear it, there's a chance to get a Greater Rift Token. If you successfully do that, you'll get a Greater Rift Key (rank 2), then Rank 3, etc.. Much like seasons, we're going to have a leaderboard as well, so you can see who got to the highest tier Rift, and what time were they able to obtain on that.
Diablo III: Reaper of Souls officially launches today for PC and PS4.