Before I show you what muslin 3 looks like I first want to show how I adapted muslin 2 into muslin 2.1 to determine how to change the pattern.
I started with a very simple alteration. Muslin 2 showed a lot of fabric being pulled into the crotch indicating the crotch length was not long enough. The trousers were also very tight across my thighs indicating I needed some more room there. I solved both issues by doing what “The Perfect Fit” one of the fitting books I own, calls a full thigh adjustment. The pattern is extended both at the side- and inseam which lengthens the crotch seam and increases thigh circumference. The red lines in the schematic below indicate how I re-sewed the seams in muslin 2 and changed the pattern for muslin 3. I also removed the gaping I had at the yoke.
These 2 changes already made a huge difference to the fit as you can see below.

Wrinkles at the knee have disappeared. Straight of grain lines are straighter and more horizontal. Yoke lies nicely against my back. It no longer looks like I am about to burst out of these.

Wrinkles at the knee have mostly disappeared. Side seam has become straighter. There appears to be less strain on the fabic on my butt.
After I changed this I noticed I could remove some of the wrinkles I still had at the front by pinning out 2 darts. I made this alteration in the pattern by slicing the pattern open and overlapping the edges to simulate the dart I had pinned out. This does not change the side seam.
At the back I thought I probably still needed to add some more length to the crotch seam so I sliced the muslin open horizontally and inserted some fabric. This did seem to improve the fit at the back and the muslin became more comfortable to wear so I made this alteration in the pattern as well. This is done by slicing the pattern open and creating a hinge point at the side seam. You can then add a wedge to the pattern by sliding the center back upwards. The side seam does not change.
After I had made all these changes I decided it was time to make muslin 3 to check whether the changes I made on the pattern were correct. Unfortunately I ran out of muslin fabric (why did I ever think 3 meters would be enough???) and had to use something a bit lighter weight than ideal but I didn’t want to wait until I had the opportunity to get some new fabric. The fit is still not perfect but I think you’ll agree this is definitely an improvement over where I started with muslin 2!

Still not 100% happy with the crotch, but overall I don’t think this looks too bad. Side seam at the thigh is perhaps still a bit too much to the front.

I still need to add more lenght to the back crotch seam because fabric is still being pulled in. My alterations at center back caused the center back seam to be a bit strangely shaped and it sticks out so I’ll need to reshape it.
How many muslins do you think I’ll end up making before I dare cut into my denim?