Could well be.
I feel way too much importance is put on graphics in games these days. For me unit graphics in Total War reached a nice level around Shogun 2/Rome 2, and I'd happily have them stick with those sort of graphics for the next few years and invest any money saved into other areas of the game.
As for reusing unit models from Rome 2 and Attila, all I can really think to say is "And...?" The campaign takes place during a transition point between the end of Rome 2's era and the beginning of Attila's, so I would honestly find it rather strange if there weren't units and unit models recognisable from both. Empire Divided is also very much a test bed for this whole concept of going back to older games and making new content, so I don't expect it to have a vast budget. Which means trying to make the best campaign they can whilst operating within their means and budget, which to me they seem to be doing.
That it costs only £2 more than Caesar in Gaul cost us in 2013 (or £1 more if you factor in inflation,) for a campaign that's bigger with more playable factions and faction diversity, which will likely sell less copies (as it's coming out 4 years after the game's original release,) is to me in part because they are able to recycle or repurpose some assets, whilst also making new ones. And I'm fine with that. I never have seen the point of making entirely new models for something, if you have an existing model that works just as well, if both will just end up looking very similar anyway.
Finally, I think the units I've seen look pretty good. Looking forward to playing with them in 9 days time.
All the Best,
Welsh Dragon.