The gold AI offers for luxuries should be toned down or the worth of luxuries should be back to where it was. They offer me 5-8 GPT for a luxury in ancient era when it's worth just 1 happiness for them - there's no way this is ever worth it for them, they strengthen me way more than they possibly gain themselves unless a CS wants the luxury. Come medieval, sure, 1 happiness (unless they exceed +10 happiness) can increase their yields by a bit if they've got a big empire and I'd understand that as an offer, but before 1-2 GPT is the most an AI should give unless they're Netherlands/have luxury pantheon.
The AI is also buying your friendship in the early game, just FYI. They can usually spare the money for a non-aggression pact like that (and will seek to do so).