Not to revive a dead thread, but I can see repair being "useful" if function was change to something like "Sanction" from FFXI and FFXIV company gear. You'd have 3 basic ranges of "gear conditions" the same, 0-100%, 101-200% and a new 201-300%. The lowest range your gear would received a "sanction" debuff or -5% to all stats, The second would be "normal" no added bonus, the third tier would be player only repairs (self of other) that uses 1 basic repair dark material, but would be based on craft levels every 10 level. The various tier would require higher skill and higher amounts of the base repair dark material.
Third teir repairs would grant added bonus of 3% experience bonus and maybe 1-3% status buff while in effect.