Anyway both got to 110 at around 50h played. I messed up with my Pal by going to Legion once I hit 100 instead of finishing treasures and bonuses in WoD. All in all, if I picked the best zones and was only trying to level as fast as I could, I would probably could have done it in roughly 40h. Note that it would have a been A LOT faster with a Monk as both Ret and Rogues don't really have a decent AoE until 40+ (45 for Ret and 63 for Rogue I believe). The daily also helps a lot. I know that leveling my Monk before the pre-patch was insanely fast. Might be slower with the changes to FoF, however.
DoTs: Assuming that the mob is going to live for certain periods of time, it is worth it to place DoTs up. If the mob lives for at least five seconds, cast Pain. If it lives at least seven seconds, cast VT. The ideal time to cast DoTs is when it would be replacing Flay, but you can substitute Blast if the mob will live longer. Make sure to cast Bolt on cd though!
With the excitement of becoming Level 120 come a lot of new activities to do. However, it is particularly important to note that you should continue to complete the story mode quests. You will undoubtedly achieve Level 120 before completing your third zone, so be sure to head back and finish the story quests as they are important to unlocking game content as well as pushing your reputation levels even higher. Each zone comes with a lot of side quests that can be ignored at first as you push your item level up, complete emissaries, and do dungeons, but when you have some time, be sure to wrap up all of the quest lines in each zone to maximize your reputation potential. Reputation is the gateway to all things in Battle for Azeroth, so quest away! Be sure to use our Quest Completion Checker tool here at Icy Veins to see if there are any missed quests in any of the zones for you to go back and complete!
To give you some perspective I leveled both a LF Ret Paladin and BE Rogue (so one started from level 20 and the other from level 1). I focused on getting the achievements I was missing for the Loremaster, so not the most efficient route by any means. I was using full enchanted heirlooms (minus the ring) and the WoW-Pro addon though, as well as having War Mode turned on all the way.
Compare that to the previous Warlords of Draenor expansion, which wasn't a great expansion overall, but still managed a prepatch that offered a pet, a title, a new version of an old dungeon with new quests and achievements and loot, a series of ultrapowerful weapons that could be passed on to alts, and a whole host of in-game system improvements ranging from a new way to find groups to a new way to collect pets, toys and appearances.
That lack of storytelling agency may soon change with Patch 8.1, Tides of Vengeance, which is coming to Battle for Azeroth soon. While there are plenty of fun gameplay changes that should make the expansion better, one of the most interesting additions is that of choice. In an upcoming quest, players will be able to choose whether they want to support Saurfang or Sylvanas — essentially honor or evil — in the struggle for Horde warchief.