That sounds like the way to go. Since SFZ doesn’t seem to support the full feature set of your original comprehensive library, maybe the UVI Falcon format or the HISE sampler project are viable alternatives to look into?
With that being said – if you could release one or two of your more traditional dry kits in SFZ format, I would be thrilled.
Yes, Pianobook tilts towards the film scoring / media composer community (I guess this is due to the close ties of the makers with Spitfire Audio and the way this project sprung off from Christian Henson’s media composition themed Youtube channel). But it’s definitely not limited to these ‘genres’ and open for a diverse range of instruments.
See for example this highly popular Pianobook-hosted drum kit, which in fact features a dry brush sound: