Here is a brief Blood Warrior discussion in Metin2 and I got it from other websites. If you plan on soloing most of the time hands down adept. BW is only good in a group with a healer, look at the Metin2 wiki. Therefore, BW is great solo and has better survivability then the Adept up until Adept gets immobile Defence. BWs are, imho, better in parties though the blood hook might get you a fair distance. Both are viable for soloing, but if you don't party much go for Adept.
This would make them a bit more viable since fights tend to last longer than the duration of our buff allows, and since our buffs wear off seconds into a fight, they are currently quite useless for the amount of effort that is required to get them up. Sincerely hope it can help you more or less.