I'd advise you to drop it. First of all, the sheer magnitude of the list of reasons not to do it is really weighting enough towards this decision. It probably does reflect your gut feeling and want about the subject as well.
The golden rule (in my humble opinion anyway..) of VCE is do the subjects you like! School shouldn't have to be boring or a drag, learning in year 11-12 with the responsibility and adulthood that come with it shouldn't be a chore, it should be enjoyable and stimulating. If you force yourself to do a subject you dont like, you will like it less, work less hard and just not want to be there much at all. It'll magnify the workload of it all.
Doing 7 subjects is a bit of a risky gambit since you're essentially discarding two years worth of work in one foul swoop. Whether you are willing to take that is up to the individual of course but i personally don't believe its worth it. Even for your bottom two, a change of 10 in your study score (say 30->40) only represents a change of one due to only getting 10% of the marks, so, 3.0->4.0. If you didnt do that sixth subject and instead worked a little harder in each of your remaining ones, you could easily gain that one additional mark. It's an even worse deal with a seventh subject. Some people have a legitimate need, want or desire to have some insurance but again, i personally dont think its worth it.
Regarding keeping your options open, unfortunately, year 11-12 is the time to start narrowing down what you want to do. Like it or not (i know i didnt like it very much), you will have to make choices and decisions, you cant infinitely stay open to all paths, at least for the time being. You say you dont see yourself in a science based career either, so, i'm not even sure what options chemistry would open that aren't science related.
TL;DR - I advise you to drop chemistry.