No, I am talking an adapter card that fits into a slot into PCI-e. That way so motherboards wouldn't have to take a major change. Also with the way the adapter cards are constructed you could have RAID cards inserted into the adapter. Don't think about it like changing the motherboard, but think about it like adding a quick expansion replacement that attaches to PCI-e.
Convenience is why this would be an interesting idea. If I have a small form factor box I would prefer not having to open up the box every time I would like to make some minor changes. If you have something that gives people the option to work on the fly, and allow them to replace items without having to whip out tools then you would be making a convenience for people. This also doensn't have to do with the size of the case considering the adaptation would still occur within the case itself, and this is all poking at the idea that we need better and smaller devices because that would be necessary to use this adapter. We can't just limit ourselves to a few IO interfaces, but we have to be willing to go the extra mile and try something new.
eSATA is the way to go with hard drives (this is SATA with a little bit more voltage and more isolation). Firewire and thunderbolt are just utter crap because apple doesn't care about the standard and there are bad patents involved. usb3.0 can only reach the speed of ide and pcmcia is useless because nothing supports it.
You don't NEED a plug and play video card
But some people do. Ask the guys working in big server farms. To be fair, the hardware is also designed so that you can relativly easy remove the components but this still is a big thing for them.
So yeah, you can hotplug pci and sata if you use a good operating system but it might be hard to do because the hardware is not designed to do so.
You don't need lots of things in a computer such as dedicated anything (exception: keyboard/mouse... doesn't have to be for one computer, but you need a set of that... for now) Most hardware design problems can effectively be wiped within 2 generations. Sure you can think of all the things that stick out when it comes to PCI-e such as USB/Firewire, but you are missing the big picture. Think of everything and anything that fits or could fit into a pci slot, and then imagine that being hot swap ready. If you have a tiny case where wiring is a pain, or just don't want to turn off your computer just to repeatedly turn it off to see if it's working you would benefit. This is like the step from IDE to SATA.
The only real application I could see this useful in is able to hotswap PCI SSD drives or NIC's. That being said, future generations could support this. Do remember at one point USB wasn't hot swappable and when it finally did start coming around (win 98 I think?) it would often cause system crashes.
I'm not sure what you are trying to say. You don't *need* to change anything in pci-e for being hot swappable because it's a software problem. You might want to change the phsyical pci-e adapter to be easier to plug and unplug cards. Or you just use a case where you can easily pull it out. I don't understand where your problem is.
I'm sorry I didn't make it clear, but I was referring to any hardware problems that could occur on the adapter card. This is because problems may occur not just in the software, but in how all the connections culminate into the adapter depending on how it's designed. You could be right though, maybe this is something that would only be useful to me. Someone else made a great statement for the software aspect already.
Do remember at one point USB wasn't hot swappable and when it finally did start coming around (win 98 I think?) it would often cause system crashes.
-HelloMrOwl