Who cares about a new class, the game is so well understood at this point a new class will only add a different collection of pixels to look at.
Make 1-70 a loot fountain (like PTR) but reduce XP earned so all pieces drop during levelling and theres time to try things and actually be able to choose your playstyle while levelling, reverse drop rates for Deaths Breath so lower the Torment the more DBs which means player farms with low gear drop rates and High DB rates or high drop rates with less DBs. Make Bounty mats a time reward, just play the game to accrue x mats for x amount of time the char spends moving and give them out if chars spend time running in circles in tristram, cos anyone prepared to drag a mouse around pointlessly also deserves the reward because its no more difficult than doing a bounty. Besides movement locking them finally levels the field between group sizes.
Remove the color of gear - make it all the same bloody colour just so all those whining about legendary drop rates can just rage-quit. Honestly anyone that whines about drop rates in 2019 can take a long walk off a short pier. Theres no need for artificial restriction, anyone prepared to pay for a AAA game deserves to experience the whole game from levelling to pushing their own ability within the time constraint of a season, no matter if they invest 4 hours a week or 40
Id also insert drops only available from campaign mode that are normal legendaries modified with other effects and make those the source of the challenge rifts, for example finnish a rift while wearing a piece of gear that makes all mobs have grotesque explosions or a Unity that gives your Templar follower a constant friendly-fire Aoe that scales up with every heal he casts or a piece that makes every rift guardian spawn together at a random point within the rift. Sets are fine as is - but surely we're at the point now where a set of gear could have its percentages and skills adjusted by the game to maintain balance for example akkhans adjusting percentages to allow using any skill reach more or less the same Grift.
Oh and the only leaderboards we see should be optional for friends and clan, if we dont know the person we have no need to know their levels and times theyre nothing more than an e-peen meter and unless the game is MMO theres simply no need to see them. The objective is slaughtering DIablo and minions not a random strangers times. If youve read this far, waste a second or two actually thinking about it, no region leaderboards means noone gives a crap about bots, paragon, hacks, or anything but their own enjoyment for a damn change.