Vogue 1059 - Alice + Olivia Trousers Tutorial - and a Question

Well, I am really proud of my first pair of trousers! I'm just so glad I got through them. Maree And Lore, I couldn't have done it without your invaluable tips.

So, here is my guide to sewing trousers. I am no expert, but I certainly learnt some things along the way.

The number one thing I learnt is that it is imperative to make a muslin. Here are the alterations I made from the muslin:

• First of all, I followed Maree's suggestion to cut the muslin one size larger, but sew with larger seam allowances. I ended up taking the pants in about 2-3 centimetres further in the hip area, directly beneath the yoke. But I did not do this alteration until I had sewn the waistband on - then I could really see where the changes needed to be made. 
• The second thing I have learnt is that I must have a very long crotch to waist measurement. I ended up cutting the crotch length at three sizes larger!    
• I also used a slightly longer zipper, and thus increased the length of the pants from the crotch to just before the waist band by approximately 1.5cm. You can see the nice length I have on them side on:

• I should have trialled welt pockets on the muslin - I really screwed up on the fashion fabric and had to do some pockets a la Rachel - which look fine, but are not welt pockets all the same. 

Pockets and rear view:

• Now, the major design alteration I made was to the construction the fly. The pattern called for approximately four different pieces for constructing the fly and fly guard. I just could not get my head around this. I am quite spatially challenged, but this was ridiculous.
• Then Lore from Sew Red Hot came to the rescue, and pointed me in the direction of this amazing video:

http://www.threadsmagazine.com/item/3831/video-an-easy-flat-fly-front-zipper

My goodness, this little 5 minute video saved my life. Thank you Lore! I'm forever in your debt. I watched this video a few times, consulted with my spatially-gifted hubby, and re-drafted the trouser leg to include a fly extension. Here is what the pattern piece looks like now:

The fly extension probably extends 7cm. I trimmed it after sewing in the zipper. It was sooooo easy!

Here is what the new improved fly looks like on my trousers (sorry this isn't the greatest photo):

And here is what they look like on me!!

Now, it is from this last photo that I have the question. See how coming up from my crotch I have that kinda 'U' shape going on? What could be causing that? Here are my thoughts:

• Is the crotch seam still not long enough?
• Or is it too long? Does that area look like it extends too high?
• Did I not trim enough on the inside seams?
• Do I need more length on the trouser length before I get to the waistband? 
• The fabric is relatively heavy - could the fabric be too heavy? It is heavier than my Herringbone, Cue and Veronica Maine suit pants material.

I don't really notice the 'U' shape when I'm wearing them, but its pretty obvious in the photos! I'd really appreciate your help and any thoughts/tips you might have!