I had relied on my ability to keep a positive cash flow to gift money when relations started to sour. I started a game last night and bumped into the Yor early ( within the first 10 turns) on a Huge map. My observations:
1) AI's will automatically send you trade in the early game - no longer a given. The Yor simply refused to send me any trade.
2) 1 IP "bug" is fixed, however I would echo Jordan's observation that it seems to be nearly impossible to improve relations - I believe I had maxed diplo also.
3) The AI (yor in this case) once they smell blood, will not let up. The Yor demanded tribute early on, which I happily paid to avoid more hostile relations, and then they proceeded to demand tribute every 5-10 turns until I was so far in debt I had no hope of getting out. Thankfully they finally decided to put me out of my misery.
4) In regards to keeping your approval rating up, it appears that losing control of the senate is more possible at a higher approval rating. I had lost control of the senate well in advance of any time before.
My game play on maso, has been to build economy and research early on, largely ignoring military buildup. Doing this, I could usually give significant amounts of money to keep the AI happy. In 1.12, I couldn't even begin to develop an economy the way I had in the past.
It would seem that a more balanced approach early on might be required. No rushing certain techs deep in the tree, etc. Although I believe diplo trans are imperative to surviving.
Those are my observations after playing and getting my butt kicked in one game. Could have been some random bad luck involved too. No question, though, the game has been made more difficult at maso.
~SDC~