You're probably only talking about losing a couple hundred bucks over the year of ownership (regardless of capacity) so do you really care?  
 
Or in a different light - a decent percentage, maybe the majority, would argue that the 2nd gen is still plenty of tablet for most users.  So if you bought a 3rd gen now, for what people were recently paying for a 2nd generation, and they improve upon the already ridiculously spec'd 3rd gen would you even need to worry about upgrading?  I wouldn't.