1. If i buy a weapon with LS / Socket now... will the damage rolls be of iLVL70 or same ? (iLVL63) using the Mystic ofcourse.
The Answer to this is NO
I saw Jaetch re-rolling his weapon but even at ilvl70 the range is fixed to ilvl63 (RoS). That maybe because he has already re-rolled it once. The first re-roll he got did increase the weapon dps since RoS has a higher weapon range than us.
It would be nice of someone would be doing a few tests especially regarding rerolling weapon damage and how it is affected by % weapon damage. Let's say you reroll Manticores damage and get 750-950 damage (2 socket, 50% ed). One possibility could be:
(413 + 498) + (750 + 950) *1.5 * 1.22 / 2 = 2389
Damage wise this does not look that good, but compared to just a socketed weapon (aren't too many socket/crit weapons around at the moment) without crit, 100% and 2 125% sockets would be about 45% more damage at 200% crit damage (other gear, base, paragon) and 60% crit chance.
A Manticore like that would do roughly as much damage as a 3450 damage xbow and you'd be able to use it almost right at the beginning.
There might be other quite interesting items. I have a 10% CC, 7% Strafe CC Maras for example. In RoS skills bonuses seem to be damage only (at least what I have seen), so you won't be able to get CC or skill cost reduction. Now an item like a Maras or Skull Grasp that could be enhanced with like 400-500 Dex might even be pretty good later on.