So i’m currently finishing up my ‘A Farewell to Arms’ meta achievement. I started off as Horde in BFA, my main got exalted with every faction, did every campaign and side quest. I have all of the achievements to show I actually did that content. About halfway through the expansion I faction swapped my main over to Alliance. The problem i’m running into now is that I can’t complete several Horde related achievements on my alts because they are locked behind reputation and the storyline. Do I have to re-farm all the BFA Horde reputation again? Do I need to re-do the entire campaign again?
Without knowing which specific parts you are talking about, more than likely.
If thing B requires thing A to be completed first and you faction changed after you did A but before you did B then yes you will have to redo thing A.
They did make getting think A easier