I think that is a flawed argument ftx, you can't compare the playtime of every faf map in existence vs map gen which has not seen wide popularity until recently. You should be comparing the average relative quality/enjoyment of playing map gen vs playing a 'standard' map. Playtime=/= fun. Look at dual gap
The point of map gen isn't to have a 'perfect' map, its to have a NEW map, and that is the point I think you are missing. Its really really fun to play something that you and your opponent are completely unfamiliar with, and actually try and figure shit out on the fly. Its not like clicking ladder and finding yourself on daroza's and knowing the first 6 minutes of gameplay require a hard wired build, with at least 10-15 minutes going by before any meaningful player interaction outside of the initial drop to secure expo. At that point it doesn't even feel like playing.
I have played more map gen then ladder this last month, although admittedly it is partly due to the 'look, new!' effect of it. That being said, I would absolutely love for it to be incorporated into ladder. I have had more then 80% of my matches on map gen end up being very enjoyable, which is more then I can say for ladder. And I personally do not see the over-emphasis on map 'aesthetics' to be such a high metric for map quality. But I guess seeing as how you don't actually play ladder maps, you need to evaluate them somehow...
My only complaints with map gen are the following: Terrain isn't always obvious (quick camera angle viewing fixes it) and that after a while (20+ games), some of the maps can seem to be fairly similar. That being said, even for some of the 'similar' maps, I could make the same complaints for a few of the maps I have seen in ladder pool. There is only so much variation you can have imo.
I would really like to see 10-20% of ladder games be map gen for a month, gauge reception then. Its really nice to have something new to play on, rather then the same old same old, and the no build order whoring aspect is amazing.