The downside is that War Mode will make you vulnerable to other players, which means you might be killed more often. Whether it’s worthwhile will depend on the zones you’re visiting and how active the other faction is on your server cluster. Heavily populated realms usually mean more players on both sides, and more conflict, but on quieter realms, you may rarely run across an enemy.
War Mode: War Mode can be turned on at level 30 through your talent window, and will give you 10% bonus XP. You will, however, be attackable by players of the opposing faction, but changes have been made so that all players have a fair shot in a fight and even low-level players can kill much higher level players, and at least not get ganked and one shotted. Note: As of patch 8.1, you can get an additional call to arms bonus with war mode on if your faction is underepresented.
Then 8.0 came along and turned everything on its head. Most of the techniques and shortcuts discovered, after 7.3.5 introduced scaling, were nerfed into oblivion. Many of the old techniques were confirmed by myself, first hand, to no longer work. I'm hoping that this thread can serve a similar purpose as the old thread, and gather as much data as possible on the fastest methods under the new system, and facilitate as many different perspectives and opinions on speed leveling with constructive discussion. I've just finished leveling to 110 under 8.1 with the exp curve.
Two new raids coming after the initial update differ drastically in size and content, depending on which side of the war you’re on. The Battle of Dazar’alor raid sees Alliance players trying to take over a city, but if you’re part of the horde, your version will see you try to defend it. Once you’ve beaten it once, you can then play the other side. The Crucible of Storms raid, on the other hand, is smaller and only consists of two bosses.
I am currently working full time on my Vanilla WoW leveling guides. Soon there will be a 1-60 speed leveling guide for Alliance, along with in-game guide versions available for my members area. As of right now, there is no members area, but if you would like to show support for my efforts into this project, you can simply donate to me via Patreon if you like (you will get some cool rewards in return). Or you can donate directly with PayPal if you like. All donations are highly appreciated and they will only motivate me more to continue making the best vanilla WoW leveling guides on the web.
I do not recommend going for TBC, although I remember Hellfire peninsula to be decent, everything else is rather slow. Instead go for WotLK, Borean Thundra gets you levelled very fast, and then you can head straight for Icecrown at 67, which is also insanely fast, although admittedly has a few elite quests. You can go to Sholazar Basin alternatively. 2 zones should get you 60-80 no problem.