I have a Panasonic AJ-D95, one of the "shoebox" type decks. I had a Blackmagic DeckLink Mini Recorder, but didn't like that I couldn't simply capture (or rather copy) a DV-AVI from a tape using WinDV or
VirtualDub. I had to use BM's capture software where I could only capture lossless. It seems only once DVCProHD came out FireWire became more common on decks.
I have seen shoebox type DVCPro decks with all kinds of bastard configurations of inputs and outputs, some with no digital ports at all, just composite and/or S-Video as well as RS-232, of course. Since analog NTSC broadcast was composite, decks were made in the early years of the format that could simply be dropped in the existing workflow at stations across the country. SDI and IEEE-1394 cards were optional.
And yes, Sony DVCAM decks not outputting Panasonic DVCPro footage via FireWire exactly is an artificial limitation.