No they are not at all final, they're still crap
Harsh but fair eh Robin.

I would agree that the gantry sides are way to slender. You either need to reduce the height of the y axis or thicken up the side plates with some of that profile section. Having now seen the whole design I would reiterate my earlier comment about increasing the distance between the y axiz rails as that will reduce the torsional force on the gantry sides and also give a better ratio of supported to unsupported plate (not sure if that's the best way to describe it?)

The Z axis is way to complicated , get rid of all the blocks and wedging plates. i.e. make the bottom plate as one piece that bolts to the bearing and is also the spindle mount. Do the same with the top plate and make it bolt to the bearing and be the ball screw mount. this will make it lighter, stronger and much easier to build.

Keep at it, as its worth getting right before you start building.