To be fair, we don't know how widespread the brainspawn really are. Considering how close the two of us were, though, it seems likely that we're not that far off.
The players aren't as close together as they used to be with three players dropping and some terrain already established as not settled, but they're still relatively close. It's just that everyone scouted in all the wrong directions. Had the Haskanara started by scouting north and upriver, the contact with Great Lactosia would have quickly been established. Also note that travel through scouted terrain is faster.
Now, I'll put a fourth of my population on some research for steel or farming or whatnot and the increase in productivity will be nearly nonexistent. Every year is about the same.
I've for a while now planned for Steel to provide a heavy smelter building that doubles alloy production speed (including strong iron and steel) - it might not be enough, but I doubt that it'll be the only technology that'll increase productivity in some way.
Also.
How does jewelry work? Do I need a special technology for it? Does the gold->jewelry conversion work the same as the wool->clothing one? Is there a jeweller's workshop?
Vanigo is correct here. When you have a "jewelryable" resource, it can be used just like wool->clothes. The tinkerer's workshop is currently the only building that increases jewelry production speed. A jeweler's workshop would have to be in some way worse than the tinkerer's workshop, otherwise the tinkerer's workshop would be pointless.
Anyway, the last thing I want to do is to bore people. Neither by making it too easy for you, nor by making it too hard to accomplish anything, nor any way else.