Before tossing the baby out with the bath water, what you'll need to do is call RCI and ask them what the discount off the cruise will be. Then you'll need to sit down and do some math.
Generally speaking the $$ saved on the cruise will be less than the dollars spent on exchange fee's and maintenance fee's. BUT, that's NOT ALWAYS true. You must call first and find out what the discount is before jumping to conclusions.
Using my HGVC points, the discount has been approximately what we paid in MF's for that year. We have made that exchange twice. Both times have been on Caribbean Cruises, one 4 nighter that was essentially paid in full and another 6 nighter that we had to come up with a couple of hundred dollars.
Determining factors seem to be the expense of the cruise and the expense of the cabin. You'll need to decide what cabin catagory, cruise line et... and check the lowest price for you cabin catagory you can find on the internet. Start by reading the forums at Cruise Critic. Their posters can point you in the right direction even though their webmaster no longer allows posing direct referals on their forums.
Once you have determinded the lowest price for the cabin catagory you want on the cruiseline of you choice, then contact RCI's cruise dept. and find out what costs are associated with the exchange and what discount your points will get you. Keep in mind that the discount may be per cabin so, if you get two cabins side by side rather than one larger cabin to hold eveyone you discount may be larger.
Only after making the call, checking on prices and doing the match can you decided if it's a good deal for you or not. I've done three cruise exchanges. The one we did through I.I. was not a good deal but, I wasn't going to be able to use the week, depositing for use next year was going to net the same problem and we were going to take the cruise anyway so, I pulled the trigger and at least got a little value out of that week. The next two we essentially broke even on the cost of our MF's but again, those were weeks we weren't going to be able to use and we were going to take those cruises so I might as well get some usage out of MF $$ I was having to pay anyway.
There have been numerous times where the money didn't work out and we didn't make the cruise exchange. MOST of the time it's not a good deal but there have been times when it worked out for us.