Yes thts correct. Nexus are purely desigened for Data Center and these kinds of setup which you have mentioned above,k as this devices has highest level of datplane forwarding and keeping in mind the future upgrade or implementation my recommendation is to go with Nexus .
But again its up to you to decide which one you would like to proceed with:
I think that you will always find that the Nexus is now recommended for true Data Centers due to the type of design and traffic that they see however it really depends on your definition of your site as a data center and your requirements.
The Catalyst 6500 series are multi use switches that can be used in Data Centres or as a Data Core in a large Enterprise which are sometimes called data centers within the company.
the Nexus are excellent switches and can allow you to use things like fibrechannel across the switches also so for that reason they are most often used in true Data Centres which have a specific role in the design.
If you just have a large network that has a number of servers and some are VMWare servers or HyperV servers then the capabilities of the Nexus or the 6500 will be fine and you will not find any problem as you have found previously.