So this is where the purple rain is falling.
Now, seriously, I quite like the color scheme you use here as well as the shape of the landmass. Personally, I don't feel distracted by the map border as it is rather monochrome and discreet in its linework. Yeah, I agree that greatly and skillfully designed big borders could distract from the map itself, I just don't think that applies here, I'd rather feel they complement each other.
I think the heart island with Javesari City would benefit from having some more minor details on the central and southern parts. A little watercourse from the mountain to the city or a few trees or a little cliff or some purely aesthetic details for example.