I did a page by page comparison of the first Volume with the first third of the deluxe edition, so far besides the translated sound-effects, the only difference was the deluxe edition cutting a “No” from a speech bubble of Puck’s, changing it from six “No”s to five “No”s (hard to tell if that was intentional or a formatting/printing error), this on page 13 in the original Dark Horse Volume. If I have time, I will do a page-by-page comparison of the next two-thirds if the Deluxe edition. But so far it seems like the “retranslation” is just the added sound effects and a few minor name changes/formatting?
EDIT:
Okay, I did a page by page comparison of the rest of the Deluxe edition to volumes 2 and 3. There wasn't anything changed (aside from translated SFX) for volume 2. However, volume 3 had a number of changes, in addition to changing their spelling of "Shisu" to 'Cis", they also changed the multiple incorrect usages of "fate" to the correct term of "causality", e.g. "laws/wheel of fate" to "law/circle of causality", which I think everyone will agree is a happy surprise. A few other small changes included Puck's dialogue on page 12/468 changed from "a Beherit!!' to "the Beherit!!, Slan on page 90/546 changed from "I'm sure he's hardly even aware." to "I'm sure he's barely even conscious.", on page 115/571 Ubik's speech bubble recounting the Count's words "I offer this woman for sacrifice" had quotation marks added to it when the original had none, Femto's dialogue on page 134/590 is changed from "this is..." to "but this is...", Femtro's dialogue on page 137/593 is changed from "be reborn" to "be reborn again". Then the english subtitle "the golden age, chapter 1" is moved from the first page of the episode to the subsequent double page spread instead. On page 206/662 Guts' inner sickbed thought is changed from "burning..." to "hot...". And finally on page 217/673 Gambino's dialogue is changed from "First one there takes all!!" to "to the swift go the spoils!!".
Anyways, I think the fate/causality correction for the Deluxe edition is a very welcome change, especially for new readers who are liable to confuse the two concepts.