Thirston tank is looking nice and healthy! Seems odd offering advice on this because I know you've been doing this for a heck of a lot longer than I have, if I give any silly pointers just smack me on the back of the head. I feel like I'm slowly learning myself plant placement and how to bounce contrasting leaf types off each other to help plant groupings stand out a little more. With all of the plants being fairly similarly colored I think adjusting the groupings and areas of planting will go a long way to making it look more focused. Usually when I'm planning something or looking for ideas I'll browse through the AGA contest image gallery
for a while and read this a few times
I'm on the other side of the coin in regards to layouts though. I tend to prefer the more trimmed ornamental look as opposed to letting things go jungle style.
A few things I think would bring it around to being a more defined scape:
Adding more hardscape/slopes or bringing the pieces you have into more of a focal point as opposed to hiding behind the wisteria. Need something to break up the solid green throughout the tank. A few interesting pieces poking out here and there will help add some contrast.
I know the Angustifolia probably looks much better in person but in a picture it looks flattened out as its being washed in with the rest of the greens, I'd move both groupings of that to the back left wall to camouflage the intake a little and make the leaves stand out more.
Either by adding some new plant types, using slope, or hardscape create some kind of midground area. The short dwarf sag in the front is a great foreground but going back it moves to sharply from low to high stem plants creating a wall.
Focal points. Kinda going along with whats above there needs to be something of interest and create some flow for the eyes. Either using hardscape, slope, or negative space you need to break up the green and showcase the healthy plants in there.