I think its a good idea to reprint monsters that go well with some of the lieutenant packs that focus on traits. I find the power level of the reprints so far to be odd. I think razorwings are really weak, yet the giants are very strong. Maybe they changed some of the stats. I hope they don't reprint skeleton archers, that is unless they upgrade them.
It sort of sounds like you have seen the new monster cards for the reprint? (As in the ones not on the FFG page). Has anyone seen the hero and monster cards for those not on the website yet? (None of my searches suggest this info has been released or leaked yet?)
I am just about to buy the conversion kit because my girlfriend has Runebound and we would like some more Heroes to add to Descent though I do find in the conversion kit heroes to be a bit unbalanced (some weak some a bit too strong). Still think the base Runebound Characters are ok, just a shame these kits won't come out before I our next campaign (none of them seem to include Red Scorpion which is her favourite anyway)