Oh, yeah, a zipper complicates things. IMVHO, I'd go with what you suggest and have a skilled professional remove the strap entirely and attach a new one. That way, if you ever wanted to put the original strap back on for resale, you could mention professionally reattached/ reinforced strap as a selling point, if their work shows (but a good professional should leave no trace, ime). The idea of actually cutting the strap sends shivers down my spine. lol
But ultimately, it is your bag and your decision. The last thing I'd recommend is leaving a bag in a state that leads you to resent it taking up space in your closet because it isn't something you look forward to carrying. Good luck, and I would love to see pics of the completed transformation!
