Apple changed IO, SSDs, bottom cases and logic boards in 2013. SMC and SSD bugs are fixed through software.Unless ghosting was caused by the SSD and bottom case...I think there were a fair amount of "Rev A" issues (as there were with the Rev A MacBook Air in 2008 and the original MacBook Pro and MacBook in 2006), but the "reporting" seemed a bit over the top. I'm perfectly happy with my 13" rMBP. It was manufactured in October 2012, and the fan is whisper quiet, the screen is excellent, and I haven't noticed the kinds of bugs people are reporting on the forums. I'm sure they are real, but I don't think this is nearly as widespread as you might think from reading the article.
Anyway, Apple apparently made some under-the-hood changes to the 2013 models, so they likely identified the source of some of the bugs.
They also introduced a new LG screen but those have problems too.
Basically we have to wait for a real update later this year for some poblem solving to occur.