Hi OP , marketing companies love to tweak designs of well known brands , but to be perfectly honest Bitcoin is a relatively new project and to change the design now would be quite insane ! The logo works perfectly for the moment 
Why change something in its infancy ( sorry) for the sake of change ?
When a logo is established , unless there is something fundamentally wrong with the organisation or logo , promote , promote and promote!
On a currency side of things - change the Colombian peso logo first ! It will be gone soon