This topic is highly relevant to my interests, so here are my 2 cents on it.
I've recently bought a KryoFlux for DOS game preservation purposes, as it represents the state of the art in that area and I have quite a lot of preserving to do. As part of that preservation effort I intend to submit them to the Software Preservation Society, who will create IPF files out of the KF stream files and send them back to me. Unfortunately, the IPF files will just sit on my hard drive from then on, since no DOS emulator supports them.
As the preeminent DOS emulator, DOSBox should definitely support IPF at some point. The reasoning is somewhat philosophical. Allow me to explain.
Any mention of "abandonware" or pirated games is highly frowned upon here. The developers seem unanimous in their opinion that DOSBox is intended for playing games you legally own, and the community opinion here on the forums is mostly the same. That's fine.
Now, as time goes on, it becomes more and more difficult for people to actually get their legally owned games into DOSBox, because the hardware to read the media becomes more and more scarce. Floppy drives are already as good as dead on new machines, and optical drives are steadily moving in that direction as well. USB versions of both are readily available for now, but that's not sufficient. First, you can't get a 5.25" USB drive. Second, you can't create DOSBox-supported images of floppies that have physical copy protection by using a USB floppy drive, so you need specialty hardware like KryoFlux or an actual DOS PC equipped with software like TeleDisk and the necessary floppy drives. (I'm lucky to have both setups.)
After considerable investment and/or effort, you now have shiny new copy protection-preserving floppy images... that DOSBox can't use. The only realistically available options to the user at this point are to give up, to resort to cracking (not illegal, but good luck finding a crack for a game made in the 80s or 90s), or piracy. (Owning a period PC that can play ye olde games is not a practical option, would do nothing to safeguard against bit rot of the original disks and the hardware would eventually fail anyway. Emulation is the only viable long term option.)
Here's the actual philosophical/ideological bit. How strong are your convictions about the use of DOSBox for legally owned games only, and how willing are you to demonstrate those convictions? Adding IPF support would be an excellent demonstration: here, finally, is a way for you to play games you own that you previously legally couldn't. It's not an easy way, but at least it's there. You could always point to it if someone challenges your anti-abandonware stance. (TeleDisk .TD0 support has also been discussed before, but going forward it will become less and less relevant, while the user base of KryoFlux will only grow.)
The prevalence of piracy cannot be helped, and even non-copy protected games will also still be pirated. Welcome to the real world, etc. But DOSBox would still be making a stand for the things the developers and the community profess to believe in. That would be commendable.
Now for some practical matters. The licensing scheme of the SPS IPF libraries is a bit exotic (modified MAME license IIRC), but GPL software like WinUAE are able to use it by relying on users installing the IPF user library from http://www.softpres.org/download (a bunch of important documentation is also available there).
While it's an extra step for the user, this is relatively unobtrusive from the DOSBox code viewpoint. IPF support implemented in this manner does not replace the existing floppy drive emulation code, but instead the library emulates a real floppy drive and feeds the client program the data it requests (this may be technically a tad inaccurate, but that's the overall gist I got from reading the KryoFlux forums where SPS folks hang out).
IPF images are read-only, so one significant new feature DOSBox would need is write shadowing, WinUAE style. The preservation of pristine disk images this allows, whether IPF or just plain IMA/IMG, would be a great addition in any case.
Finally, there's the overall positive halo effect on the whole retro DOS scene. DOSBox adding support for IPF would be a significant increase of potential IPF users -> sales of KryoFlux would increase, supporting the SPS -> more games would get sent to SPS and preserved. It's a win-win-win situation 😉
That's about it. I hope you recognize the value of IPF support. If you don't have the personal interest or development time available, I ask that you consider something like making IPF support for DOSBox a Google Summer Of Code project.