Agreed.
You and your cousin (especially if he has been doing Gunpla for 13 years) need some practice and lessons in basic building and following clearly drawn out step-by-step instructions. 4 days to build 1 MG is waaay to damn long, it took my 8 year just 6 hours to build a MG NT-1, now mind you I don't think he is ready to build a PG, but on average I can build one in about 10 hours (and PG Zaku is one of the most straightforward PGs, not Strike). Now, by build I mean exactly what you said, just snap and build straight oob, no painting or anything else done.
So either you guys need to get some schooling on building or you are overly exaggerating the times it took you to put together them toys. YES TOYS. Lets face it, current Bandai Gundam kits have been made for a younger market and don't compare to anything I grew up on. The Gundam Kits of old were very much like the Hasegawa kits of today (except old Gundam Kits lacked tons of detail) in that you needed glue, paint, and some skill to complete.
Now I love Gundam kits (even some of the new ones coming out), I'd bought them since I was a youngling, but they are now just build 'em yourself toys that do not require much on the part of the builder (can't call the person a modeler unless they paint and take care of seamlines ) but they do not compare with other kits as far as detail goes, such as Fine Molds or Hasegawa.