Sure, but I'd much rather receive 300

up front for my luxury, and pay 10

/turn for 30 turns for his. The computer doesn't realize that the two deals are not equivalent, which is pretty strange since it does realize that

now >

later when making loans. Although I'd argue that it doesn't fully appreciate the degree of that relationship.
Yup.
Well the ideal solution would be for the AI to have a decreased value for "per turn" v. "lump sum"
say Interest factor * Trust Factor
Interest factor... works both ways.
At 80%, An AI looking for a fair deal will give you 10 gpt(30) for ~240 lump sum gold.. and vice versa
(I think 60-80% would probably be good..only take loans when you need the money now)
Trust factor.. works one way only (this is "how long will you uphold the agreement")
[in the other direction, the human player can get info on the 'AI trust factor']
Trust would be capped any time the human player ever broke a treaty... with Anyone.
So if you stopped delivery on a 'per turn' treaty 20% into it, then the AI would assume that you would NEVER go above 20%
Trust would slowly increase (but never above the cap) when you fulfilled a per turn for lump sum agreement completely.
Trust would be much lower for an AI that was planning to go to war with you... or had reasons that you might go to war with it. (so if a player is labeled a warmonger, the trust factor goes down)
Trust would have a starting value based on game difficulty.
ie on Prince.. starting value of 90%
Deity.. starting value of 50%
Of course what that boils down to is eliminating lump sum gold in almost every case. (you won't 'take loans' from the AI except in extreme cases)
I think it might be simpler+easier to just eliminate lump gold entirely.
As for the other "lump" supplies...
Defensive Pact /Agreement to Attack can also be considered ongoing things. (ie if they agree to attack someone, and they make peace with them, and you don't... then the have defaulted on the agreement too)
For that matter so is a research agreement
Then all that we're left with is cities. Which are complicated to value as is.. since they can Cost you Happiness. (and gold)
Perhaps cities can be left on the
1. Peace Table
or
2. Gifts/City Exchanges