Hello, long time on and off player, short time lurker, first time poster.
This guide is great overall and it was a good starting point for me, but I think it may be downplaying wide play a little. I've been playing wide excusively this month on immortal, and have found several instances where it's not just fun but also
ideal.
I think this image should be enough to explain everything.
This is one of the strongest starting areas and execution I've found for going wide, even though I messed up with National College timing by forgetting about it and delaying about 50 turns in exchange for an expansion spot that was not in contention(the bottom left one on the minimap next to Venice). I'm probably strong enough to go for any victory except cultural at this point.
I don't think the biggest starting location requirement for wide play is room, since you can always make room. In this game, I opened up by building my first expansion city at Osaka and then spamming archers to pin down the Netherlands in a very long war. The war eventually ended in me upgrading all of my archers to composite bowmen and him surrendering Rotterdam. I then went to war again just to take out his settler and got a peace treaty with no strings attached. I have no warmonger penalty at all, Netherlands doesn't even hold a grudge, and I made room by pinning down my nearest neighbor.
I'd say the biggest requirement for going wide is
religion. Religion is the biggest incentive to go wide, since more cities is the only way to get more faith production. It's also the biggest requirement, since it will give you the happiness that's needed to expand faster and harder. If your starting location does not give you a strong early religion, it's not a good game to go wide in(although you always can if you want).
So the two reasons why I consider this the ideal starting location thus far for me to go wide are: 1=Mt Sinai, and 2=Gems. The great thing about gems is that it doesn't need to be improved to immediately start giving +2 faith. As I stated earlier, my first spot skipped everything and went straight to Osaka just to work Mt. Sinai. In fact, it stayed at 1 pop for a very long time doing only that. I then got Tear of the Gods pantheon for the Gems and Pearls +2 faith.I had 7 Gems very early in the game pumping out 14 faith, and 8 faith from Sinai giving me 22 faith before anyone else has even founded a religion. I got both Mosques and Pagodas in my religion, and it just snowballs from there to give me even more faith.
I do agree that going wide is usually not ideal and mostly just for fun, but I just wanted to throw in an example of a starting location where, if executed properly, the wide way is the best way.