So definitely some more black lines around the individual items like the 3 sun's from the backfield, the color of the crescent from the other color, the wyvern from the field, and the fields from each other to help everything pop. When you're done painting you can do that with a sharpie and it'll do wonders.
The purpure could definitely be darker in tone. The imagery fills it too much and could be a bit smaller in relation to the shield and the field. What kind of shield will this be on? Because that will change how it needs to be done. Does it pass the 30ft rule?
Follow this link and you can get some ideas of how others have crafted theirs creatively including mine (note: uses some clip art)
West Kingdom Roll of Arms.
Personally I prefer less busy devices. 2 good examples of busy devices that I spent a lifetime seeing from across a field are my mom's & my stepdad's and I can tell you that quite a lot of both devices drop out from even 30ft away on the shields they were put on.
My mom's which is put on a bunny round.
My stepdads which is on a sidegrip round.
