What class? I was getting plenty of Greater Lair Keys from War Plans etc but didn't really run them as there was no loot that I needed other than mythics, and for mythics I had 3-4 mythic tribute runs which along with the shards I was able to turn in to the mythics I needed. By the end I was running T12 and pit 105 with ease and could easily have pushed on if I could be bothered with incremental upgrades of chasing a 1% here a 1% there.
I think the biggest differences in the end and that will hopefully continue to have a big impact going forward is obviously number one the cube once you start getting mats for it, with the cube you can reroll stats on your gear and target what you need. And the other is no longer needed specific items to unlock the chests at the end of lair bosses, means I can run the bosses I need rather than have to keep waiting for/or farming specific drops. And another is War Plans, War Plans are great, being able to choose your own path and tweak the rewards through the War Plans tree was nice as well.