Rotation might be a little better, but I do not think it is the proper solution. I think the correct solution is a bit more complicated. It should be easier to implement for 3d rendering than it will be for the software renderer in prboom3ds.Sorry, looks like I'm blind.
Thanks.
EDIT :
Works great! But the same as prboom3DS, the 3D effect is just a translation of the same scene -> it misses a little rotation to achieve best results :-)
It's a very good start; very good port!