Many (all that you described and more) changes between the first year AI (2008) and the latest (2012). The 2008 was a great boat, but by the 2012 model Hobie has fixed most issues than some people have encountered.
A 2008-2010 in good shape is probably worth between $2000-$2600us used, depending on any upgrades (some were free) and additions included (carts, sprayskirt, etc.)
Good luck deciding, but go for it (which ever you decide).

_________________
http://KayakingBob.com - - - - - - - - - - - - - - - - - - - - - - - - - - - 2007, 2009 & 2010 Hobie AIs and a 2010 TI