I agree on the single look. So maybe a new pick guard and the one pup mounted closer to the heel. When I pluck the strings up there instead of over the current pup, the does improve to my ears. Just a thought......
Just because it sounds better to you to pluck there doesn't mean that a pickup there will make the bass sound better. A second pickup always results in some phase cancellation of upper harmonics. That's not necessarily bad, but it does change the tone. That's why I wondered why you would add a pickup if you like the tone as-is.
Your bass, your choice, of course. If it doesn't work out, you can always use the empty pickup cavity to store a plug of your favorite chewing tobacco.