It's easy. Just beat the campaign so you unlock all difficulties and search for matches online. I think you have to find them in Torment VI so you get paired with cheaters. You will level up REALLY fast. I got all my classes to level 70 in less than 2 hours.

I think the 500 bounties and hardcore mode trophies are way worse and those are the ones preventing me from getting the platinum trophy.

Wait for the next patch, 2.3. It will make the bounties worthwhile, having ingredients needed for the new Kanais cube recipes.

Hardcore is piss easy. Just roll a Barbarian and spin your way to victory, like I did. 

Nope... doesn't seem worthy, i played Diablo 3 on PC on release date and it was really boring, ended up getting a refund.

Not a fan of the art style to be honest.

The problem is I already used it in my normal playthrough... it would be too boring to do it with him again...

Only finished the game once so far with Crusader...it was so trivially easy I haven't worked up the desire to go through it again. Part of what made Diablo great was its unforgiving nature, and it's just nonexistent in #3.

Maybe Diablo 1, but 2 and Lord of Destruction were pretty easy as well as long as you spent some time optimizing your gear. 

Gotta say...Cain's Set makes leveling kinda stupid.

The Gem of Ease is 100 times better than Cain's Set.

•  Take your strongest character, run Greater Rifts until you can level your Gem of Ease to Lvl 25.
• Once you've got that, you can socket the gem into the strongest weapon you've got and equip it on any character (like say a brand new one). 
• Set the difficulty level to Torment VI and start killing stuff, the high damage on your weapon will insure that you can kill T6 monsters even at Lvl 1 and the XP boost from T6 and the gem will make you go from Lvl 1 to 45-50 in like ten minutes.

If I could get one to drop for me...I'd love to have some fun like that. But at the moment all that I have is the Cain's Set and Leoric's Signet.