The devs said that they will use “classic wows graphics” but that they will also make them compatible with modern hardware. So they should look like classics original graphics as long as you are still using a computer monitor from back in the day. Basically it will be something like playing the old school super mario games on a 4k TV with some adjustments to make the game work better with the screen. Whether or not this is just fine tuning or an increase in resolution, I honestly can’t say.
Personally I like the old graphics and I would not mind if they added redesigned version of them to the game as an option. My only issue is that I am not a big fan of the new models, so if they were to update the graphics I would prefer they make new classic models that don’t look like the ones in retail.
So to sum up what my stance is:
keep the old models in the game, but give us the option for more modern graphics and models that aren’t based on retail.
As far as models are concerned, doesn’t blizzard still have the older models still in retail. On a second note, blizzard did confirm during blizzcon that they still had the old files from classic 1.12 on a devs personal backup (Probably new blizzard would have to cave one day when it came to classic servers). The only issue with it currently, is that they still need to fix all the out of date code, such as the lamp posts that are shining purple due to bad code.