There are three "presets" for distortion. Birger, Victoria, and HoI. Any given flag with any given distortion will always come out the same way. It's not like I choose to add more ripples to certain flags.
If your flag has details that would pop up on one of those ripples, it's not going to look good in certain styles. If your flag is not in 70:44 (1.59:1) aspect ratio, it's going to get scaled when you turn it into a flag. You can correct this for individual flags by making the canvas bigger (you add empty space until the aspect ratio is 1.59:1) and then you have to mask that empty space to make it transparent. Your flags ends up smaller, but it doesn't get distorted by being scaled improperly. This is a lot of work per shield and flag.
That flag you posted as an example uses the exact same distortion as every other _Birger shield, but for that particular combination of detail and coloration, it doesn't affect the flag as much. There's absolutely nothing I can do about that. The scaling/masking issue I could do something about, but I generally won't because it takes way too much time per flag. If it's an odd-shaped flag (swallowtail, square, etc.) I'll do it because it's the only way to get it done, but for a standard rectangular flag, if the image isn't in the proper aspect ratio, and I can't find one that's closer in a 5 second google image search, I'm not going to take the time. There's also the issue of flags that have small details that aren't going to come through clearly at 70x44 pixels in any aspect ratio. I have shields for the US flag from 48 to 70 stars. I'd bet money people couldn't tell the difference between most of them in-game.
I understand that people are going to be picky, and I'm fine with that. Anything I post here is with the understanding that it's as good as I'm willing to spend time making it, and if you don't like it, it won't hurt my feelings if you ask someone else to take a crack at it. I just have to be honest too that I'm not going to spend an hour making sure a flag for St. Petersburg Florida is detail perfect at 70x44 pixels.
EDIT TO ADD: I created a thread the other day with
a quick tutorial on how to make flags. If you're any good with Photoshop and you want to have a go at making flags, read away! There are links to both of the original "Easy Flag Maker" threads, the original of which has a great tutorial on doing more complex flag editing, including flag and shield masks.