Conversely, as someone who plays almost exclusively Classic Mode games, I think it's a vast improvement over the generic-looking simulacra we were using before. It means that when I do spend time completing Realms, or doing the occasional Duel, and getting new and improved gear, it actually now means something to me in the mode that I play the most. It's like Fashion Souls, except in Chaos Reborn. (forgive the Dark Souls reference)
Of course I can see that it might not make total sense to have a whirly chaos staff animation when you only have a generic staff, but that's only going to be confusing to new players, perhaps.
The simplest solution is - of course - to have an on/off toggle in the options. Perhaps even turn it off as default, so that new players aren't confused by the inconsistencies, but please don't remove one of the actual concessions that's been made to Classic Mode that makes it more rewarding for we resilient few.