I agree with TUG and spending 6 months getting educated and working through the options. The first question is whether buying any timeshare makes sense. If it does, what's best for you is totally dependent on you situation, what you like, where you are, how well you can plan, the list goes on.
I can tell you what I did and why and how I've changed over the past 7-8 years. My first timeshare was DVC, resale, OKW with free tickets in 1994. A couple of years later I decided I wanted to try other places to I looked around. I wanted a Marriott but for trading. I ended up buying a non Marriott Aruba week very cheaply then later a shoulder season Marriott at Harbour Pointe, HH. I've used them exclusively for exchanging having never been to Aruba and only staying at HP one but in a much better week and unit that I owned. Since then I've gone to a more buy what I use approach buying Marriott's Grande Ocean and Surfwatch, selling the HP week and buying a MX resort. I still own Aruba week but not the one I bought in the 90's. And it's likely I will convert my Aruba weeks to Bluegreen points in the next month or so. I've since bought and sold a number of resorts and week moving up the ladder.
My current holdings are 3 summer top Marriott weeks which I generally use every other year and rent off yeas. A MX resort that work on points which I also use sometimes and trade or rent off years. The aruba weeks which I plan to convert to BG points and can use the points to pay the yearly fees giving me about 2 weeks a year totally free. Two DVC contracts (BWV and OKW) but have since owned and sold two other OKW contracts.
The problem with your scenario is that most weeks that cost $15K aren't worth it. And the ones that are worth it are frequently actually more expensive. And like DVC, it does not make sense to own a BMW and trade for a Chevrolet. Thus you're back to how YOU will use it, when you can go, how far in advance you can plan and where you like to go.