i was thinking what if the heralds powers worked differently then the knights radiant in that they only had access to one type of surge and each herald had a different one instead of the duel powers the knights had.
also there is that theory that sezeth has a honorblade and the three lashings he uses seems to all be gravity based as least to me the sticking things together always seems more gravity then pressure.
on a side note using a full lashing on two objects that have no friction could you slide them around as long as they remained touching
while on the subject of heralds is there a list of known or suspected heralds from the first book around