Wedding and event videos fall squarely in this category. No bride will be okay with spending $1,500 for a Vimeo link.
And cheap USB2 keys that hold a couple hundred times as much data as a DVD don't exist. Nope, they do, and are far more convenient and resilient to damage than optical media.
You also need storage space. HD video, art assets, high resolution multitrack audio projects, and CAD drawings aren't exactly compact forms of data, y'know.
Use the local SSD as a buffer for high speed work. Copy from network to local, work, upload back. Clear space, move to next job. If you require high speed links to large disk, use thunderbolt to add dual 10GbE for iSCSI or dual 16Gb fiber channel.
That's a rather broad brush to paint with, especially since disk I/O over the LAN starts hitting a ceiling pretty quick. This would be easier to swallow if there were a PCI Express slot to add a 10GigE/Fiber/Infiniband card, but they did away with that, too.
False. See links above. Thunderbolt IS PCI Express. It's on a cable instead of a slot. Whoop de do.
I'll agree that the GPU situation in the current Mac Pro is rather underwhelming, and a product of a design decision rather than making available options to the "Pro" customer. However, the GPUs are mounted with BGA connectors, and it would be feasible for someone to use a logic analyzer to figure out which pins on the connector are PCI express, which are DisplayPort, and which are power allowing for someone to make a 3rd party GPU upgrade card (if they could make it work with the thermals), but the market would be so small that nobody would ever turn a profit at it.