I don't know if anyone is still interested, or this has already been done, but I made a ripper for the WORLD.WDB file. It extracts most of the models and textures and outputs them in .obj format. I think it's just the models with animations that don't extract. Also the normals for the model faces will need to be inverted.
Github source: https://github.com/LiamBrandt/WDBRipper
Github binary download: https://github.com/LiamBrandt/WDBRipper/releases/download/v0.2.0/wdb-ripper-v.0.2.0-binary.zip
RRU download: https://www.rockraidersunited.com/files/dl-r30/
The tool extracts 451 out of the 592 models, whereas the old one only did around 300.
The minifig models have also been extracted, although the wdb ripper has not been updated to reflect it. I wanted to get this implemented into the extractor, but I honestly haven't had time. Instead, I found a messy way to get the models out, so I have them for anyone that wants them. Although most people already have minifig models, these are the original ones. Make sure to read the README file.
Minifig models:
Dropbox: https://www.dropbox.com/s/ygssmf0lwwrey2c/extra_li_models.zip?dl=0
RRU: https://www.rockraidersunited.com/files/dl-r438/