I totally understand. I had this dilemma for a long time too. And my case is the same as yours; my style is very casual and my outings are too so I end up using the Lou and haven't even had a chance to wear the Mini Lou. But I got it for the same reason; because it is so beautiful.
Sometimes beautiful doesn't mean practical and just because we admire a bag, it doesn't mean it is a good investment for us. My Mini is still brand new and just sitting in my closet. I consider a waste of money and space. I am thinking I might want to sell it and maybe get the YSL Puffer pouch or the wristlet in gold or dark beige to have as a dressier option instead, since that would end up being more appropriate for a wedding or fancy event than the Mini Lou which is more of an in-between bag.
I did notice this new Lou Camera Bag does have a very long strap. I agree with that. I am 5'5''-5'6'' and I have it in the second to shortest setting. I think if you get it in store, they can punch an extra hole for you, if need be. They can probably do that at NM, Saks and
Nordstrom too.