Is it not playable in deity? I know about WB/scenario/barb techs but this still doesn't recreate the 2nd settler. I also know I'm pretty dumb dumb at that sorta stuff though, since I've never even got the HoF mod to work. But 2 settlers would obviously have a huge effect in how quickly the gold/fish spot goes to Khmer. Regardless of if that is a solid reason, it's not one you could divine at t0. I get the idea of moving closer inland - all else even that's the way to play peninsular starts. But in this case, I feel like it's safer to assume you will get cut off from leaving your peninsula, and I'd rather have the extra city to break out of such a situation. With coastal commerce but low cottage potential, and Izzy, the second I see horses I would have tunnelvisioned on HAs. I'm very confident in rushing Inca with 3 good cities. Building another settler / wb + moving them all the way over there (and not teching HBR) exposes me to a lot of risk if I lost the city spot at the last second.
I can see the pros of building the 2nd city 1 tile further west. Given my assumption of an early rush (and especially the revelation of the horse tile) building where Shakra did seems obvious. But if I wanted a more long-term 6 city empire I would have been tempted. Don't have to monument for the crabs. The city takes up the worst tile available instead of a nice riverside hill. And giving that city two hills that could be mined instead of 1 hill after border pop. But in early rushes whip is king not mines.
I'm actually not entirely sold on early sailing. I'd like roads anyway for an early attack. Lighthouse & granary may be overkill early, and we're already EXP for granary.