Not really got anything to say about this, it just struck me as really odd that this page, with less than 20 replies, has been viewed over 14 thousand times
I suspect the (now) 15½ thousand readers of this post may be people Googling for "Gallifreyan Language" or "Gallifreyan Writing" and finding this post. This shows that there must be a lot of interest among fans, who would love the Gallifreyan writing system to have rules set in stone, and that there is a need for an English<->Gallifreyan dictionary!
I don't think there is actually anything deeper to look into than the fact that the designers liked particular designs. I don't think they were intentionally trying to write script with the images.
I suspect this too, but I feel that when these designs were created, they weren't completely random. They all fit loosely within a circular theme, and looking at the symbols for 'Thrust' and 'Decelerate' at the top of this thread, you can see that they are opposites. How have the designers tried to make the symbols 'look' like the words they describe?