Fanless cooling with decent cool block on the switch chip and on the SFP+ cases, would just be proper thermal design. The sfp+ modules need at least as much cooling as the switch chip! Nothing more than that!
Twelve in state eight 2.5 ports seems possible to me as well. Also at this moment in time.
Note that I used to have a CRS317 with the same bad thermal design. Noisy fans cooling ^nothing^. The cpu cool block, was not cooled by the fans, and the SPF+ modules also not. So also not. So lots of improvement options in regard to thermal designs