I also desire and wish for more than 32-channels from the IFFW card but that is not likely to ever change with the current IFFW card. I'm always needing to pre buss and stem tracks to make them fit. While that can frustrating, I think how fortunate we are to get solid 32-Ch via an outdated FW400 protocol.
I'm also always wishing I had more than the 16 soft inserts as well which is so limiting compared to all the I/O the DM-4800 offers that I could make use of.
There is a work around to the 32-CH IFFW limitation but it gets expensive and complicated. Use a different audio interface with it's I/O connected to the DM-4800 which I am planning to do.
Back when I bought my DM-4800 shortly after it started shipping many years ago, I had high hopes that there would one day be a MADI card for it to better support all the I/O it has but that never happened. After all, MADI has been the Gold standard protocol for many years for audio products that provide high I/O channel capability that also includes extremely low latency by design.
Within a year I won't need to use the IFFW card as I finalize plans and budget to go to a 128-CH MADI solution via Thunderbolt using 64 of those MADi channels in the short term specific to the DM-4800 via ADAT, TDIF, AES and even analog as Slot-1 will have much more value to me for the extra 8-CH I/O that it can provide.