I agreee.
The bigger space will be more comfortable.
I'll make it.
Actually it's already bigger than in current skin

Regarding custom buttons:
One custom button probably is enough.
Bearing in mind that any button can be long pressed - you have enough controls on home screen.
I'll think about it.
I'd like to see interface like this:
1. EQ.
Short press opens EQ dialog.
Long press Disables or enables it.
OR
Short press switches between presets.
Long press - opens dialog.
2. Change view. Two possible scenarios:
Short press - instead of playlist shows the album art. There is button back to playlist view somewhere.
Long press - instead of playlist lyrics. There is button back to playlist view somewhere.
Or IMHO the is a better option.
On each short press it switches: Playlist view -> Album art view -> Lyrics view. That would be more intuitive, one simple and easily understandable icon would be needed. No need for button back.
Long press option still unused.
3. Bookmark. Same behavior as now.
4. Playlist.
Short press - goes to playlists view.
Long press - music browser.
5. Edit current playlist/add/open/bulk delete
There is space for only four buttons right now.
So possible options:
Move EQ to play/foward/rewind area. And leave no custom button.
Edit current playlist/add/open/bulk delete options pops up on long press on any song in the list.
Or let user customize those four buttons as he currently can customize the menu.
I personaly don't need alumb ar nor lyrics.
But many many people do need

.
That's why customization is a best option IMHO.