This tank reminds me of one of my tanks right now! (Except my tank is 10 gal, and up to its ears in sagittaria rather than tenellus.)
I'm excited to read this thread because I'm dreaming of getting a 40 b myself. What I love about this size tank is the depth from front to back. Most other tanks seem so narrow to me. I think the problem is that I actually want a pond in the house!
But anyway, what I wanted to say, which is actually related to your tank, is that I wish you would use that depth a little more to your advantage. When I look at the pictures, if I didn't know this tank is a 40 b, I might not realize it - though you have a lot of plant mass there. Especially over on the left side. Somehow I'm wanting more variety in texture or shape from the plants there, maybe something less grassy for contrast with what is there. I was a bit less bothered by it in the pictures from March, as you left the plants in the back a bit taller, but even then I crave more contrast so that I can see how far back the tank really goes. The right side is better with this because of your hardscape and crypts and whatnot in the back to give a point of reference for the space.
Of course, I can't really talk - right now my 10 gallon is kinda just a jungle of grass with zebra danios flashing by every once in a while. But hey, at least it's all growing!
Also, I agree with what bsmith said about hardscape.
Also also, that gold colored angel fish is super pretty!