Could you provide some more information (time investment/how far behind/etc) on leveling as blood when intending to main another DK spec? While I don't enjoy raiding as a tank, I enjoy tanking in dungeons with friends...both while leveling and after max level to get ready for raids. With mythic dungeons being another source of powering the artifact, I will probably look to tank some of these as well.
I know that the xp needed to power up your weapon increases drastically after the first 13(?) levels, but is there any info on obtaining a couple of weapon talents to enable dungeon tanking (maybe not optimal but sufficient), and then focusing on a main spec?