In answering the OP's question, he is asking specifically about entry level kites and learners.
I would suggest the biggest leap in entry level kites was the SLE in 2007ish. It allowed significant range and depower through bar release and therefore made "bailing" by letting go of the bar when learning a much safer and effective thing to do. Relaunch was also improved in the SLE and together they made it very easy to "exit" reasonably safely when in trouble and then quickly relaunch for another go. Up until then releasing the bar was by no means a get out of jail free card and was frought with it's own issues.
Since then the only real improvements that will overly effect a beginner is reduction of bar pressure and some better manners (stability). Therefore I would suggest that while there is no doubt a newer kite will almost always be better (some exceptions), for a beginner any entry level kite from 2008 onwards will let you learn technique and progress at a similar rate as newer kites. Popeye arms are a risk though on the early SLE's

Wax, I agree there has been some good progress since then 2008, but the changes/options mainly effect more accomplished kiters who are looking for particular characteristics in a kite, and finer contol. Until you get to a certain level, turning speed, multiple attachment points, response, boost, float, one pump etc really make little difference.