I have been thinking about this for a while, and I want to share my reasoning behind my thoughts:
I maintain that the most future proof format for sampled instruments is SFZ.
SFZ formatted instruments containing properly named multisamples with loop point metadata stored in the WAV file are the most compatible and most future proof medium for sampled instruments. They are compatible with everything having to do with samples.
Think about it. At its highest level, most samplers import and read SFZ mapped instruments. Often the the most important configuration data can be imported into the sampler as well. So, at the highest level, SFZ is not only compatible with SFZ parsers such as sfizz, sforzando, LinuxSampler, etc, but with nearly every available sampler on the market.
But what if there are some samplers that can't read and import the SFZ instrument information? That's where a properly named and looped set of multisamples come in. Nearly all samplers, even those who can't read SFZ instruments can at the very least read the WAV files. If the WAV files are properly named and looped, the majority of the work is already done--even for these samplers. If the loop points are already assigned and you know the root notes and such for the samples, all you have to do is map them to the sampler you use. It's a little more work than being able to completely import the complete instrument data, but it still saves a huge amount of time from having to build a sampled instrument from scratch. At the absolute lowest level, you can at the very least import WAV file samples into any sampler out there. This provides future proofing for your instruments, no matter what sampler you may use in the future.
Let's compare this future proofing capability against common big name samplers. Nearly all of the "popular" formats for sampled instruments are encrypted, which tie those formats to the single specific sampler they were created for. What if that sampler is no longer available for you to use? What if the company goes under? What if your preferred choice of sampler changes? You are completely out of luck, and your sample investment is rendered useless, unless you can find someone to buy them from you.
There are other formats that are good as well, and don't encrypt their libraries. With these formats, you can at least use a converter to change the instrument format from one type to another. Among these formats, you would find Soundfonts, Decent Sampler instruments, etc. But without the converter, you can't grab the WAV files. For this reason, they are not as future proof as SFZ files.
Over all, for all of the reasons mentioned above, SFZ is the most future proof format for sampled instruments. Is the format perfect? No. Basic scripting for simple instruments is not difficult, but it can get very difficult to do complicated scripting with SFZ, especially since there isn't much official as far as GUI-based instrument creation. That is a hurdle yet to be overcome with SFZ. However, there is a common denominator of basic opcodes that nearly every SFZ parser must use, and that common denominator of basic opcodes are the ones that I mentioned that are very easy and basic for scripting. Therefore, even despite this drawback, SFZ is still the most future proof format in existence today for sampled instruments.
, assuming there was also plenty of interest 