Honestly, it needs more work. I would say that is less of a custom theme and more of a simple wallpaper replacement, of which anyone could do themselves.
The issue with the majority of the themes so far in this thread is that they do not take readability and visual design into account - like in yours, the text on the top screen is absolutely unreadable. It's a mess and clashes drastically with the background. All you need is to take that area into account when designing and make it a lighter tone or add a box for the text to be displayed over.
As it stands, your theme currently drastically affects usability of the HBL and I personally wouldn't use it.
An example of an effective theme would be this one I found on neogaf (the user hasn't posted the source files sadly)
See the difference there in terms of use of color and readability?
This one here is fantastic too:
Further to this, if these themes are being added to the 3DS themes site, they need to be screened and held to an acceptable standard before being featured - not many of the themes in this thread so far would honestly be worth downloading and would actually bring the site and collection to a lower standard against those themes which are actually decent.
Creating a custom theme isn't as simple as just slapping in any old wallpaper and calling it a day. You need to approach it with a design based ethos and actually put effort into it.