Do you really like the current 3717?
Will you be able to afford another IWC in a year or two?
If the answers to the two questions in the above are "YES", then I would suggest you to go get the 3717 first. Despite what my foot note says, you can always buy more than one IWC... :-)
Knowing that IWC will refresh the pilot line next (this) year, the current 3717 will surely stop production soon (if not already). If you like it and have the budget for it, why not buy it now? Otherwise, in a year or two, if you decided you actually wanted a 3717, you may not be able to find one new. (On the otherwise, if you want to buy one of the newer Pilots then, you could always do that later).
Usually it takes a few months (maybe even 6) for something that has been showcased at SHIH to show up at your AD. (Boutiques will probably get them first before the ADs).