I'm not trying to be condenscending in any way, but Diablo pre-70 is not really supposed to be all that difficult. Much like World of Warcraft, the grind to max level in Diablo is really just there to get you acquainted with your class skills and the general mechanics of the game. It'll be fun the first 1-2 times you do it, but after that, levelling characters just becomes a chore (At least for me it did). I don't know if you bought Reaper of Souls, but honestly, the game isn't really much without it. The endgame content which is available at level 70 is tons better than what little is available at 60. In regards to your points on abilities, I'll be honest with you: While levelling, it pretty much doesn't matter what abilities you use. There are some that function really well without specific legendaries and thus will make levelling easier, but that's the thing about Diablo 3. Abilities fluctuate in strength depending on the gear you own, and I am not just talking about flat damage increase from better stats. Endgame sets compliment different abilities with set bonuses and unique legendary suffixes and most of these cannot even drop below Torment 1 difficulty. For example, Monks can get a set that changes various aspects of Dashing Strike (Such as causing it to use your Spirit Pool when it is on cooldown or increasing it's damage dealt by 12500% after you use any sort of Spirit Generator) and suddenly with that set, you can reliably use Dashing Strike as your primary damage tool. I don't want to discourage you, but all Diablo is, is a grind. It starts as a grind to reach max level, then it becomes a grind to grab entry-level endgame gear so you can do at least Torment 1 difficulty, following that it becomes a grind to obtain the specific class set/legendaries that you need to make your ideal build and finally it becomes a grind to get yourself the gear that will allow you to reliably farm the highest Torment level possible. In-between that are Bounties, Rifts and Greater Rifts, the latter here being the "true" true endgame with online ladders and leaderboards. If the idea of cutting a swathe through thousands upon thousands of hellish creatures in the hunt for that one legendary that will complete your build doesn't seem appealing to you, then I'm not sure Diablo is your game.