Where have you read that the 3090Ci has no improvements from the previous model? I'm not aware of any comparisons, professional or otherwise. Not saying you are wrong, just that I'm curious how you know there were no improvements.... where you may have read that.Well the concept center is different from the 3090. From what I know, the 3090 has no improvements from last years model unlike the 3020i that did improve over last years 3020.
I think the 3090ci is a little deeper than the previous model, so size-wise they aren't exactly the same. Whether they changed anything else, bracing or whatever, no idea. Although they did add better bracing for the 3020is, so logically they should have done it for the center too.