funny you brought this up because we are at the same decision point. Our 9509 and some blades in 9513 are going EOSL so we need to make a decision of what to do next. Just like you we have had significant consolidation of the last 5 years, UCS, big VMAX AF instead of many VNX/VMAX. Given that price for a director class switch is almost x4 as expensive we will be strongly considering 9396 as our future core switches. Yes we will not be able to use 32g blades, we won't have access to the new fancy analytics functionality but it's just nearly impossible to justify that price difference. If we ever need to expand beyond 96 ports it will be PITA because you have to start dealing with ISLs etc but the way things are going we'll be expanding in the "cloud" versus building out huge datacenter FC switches.
I was at the same decision point about a year ago. We had two MDS-9509s at our primary and 2 at our DR site.
You are correct about the $ on the 9710s...they are very salty. My wonderful DELL/EMC pre-sales engineer wanted to sell us 4 9710s.... but I went with 2 9710s at primary and 2 9396s at DR site.
All is working great at both sites...I have 160 of the possible 192 ports populated on a 2 SAN 9396 fabric and the CPU/memory on the 9396s are barely registering work.