Become a vassal... (and VanillaMOD)

I have never successfully pulled off forcing the AI into accepting my demands to become a vassal. Both weak, friendly, allied factions and ones I have all but annihilated have laughed me off as if they wouldnt benefit/avoid destruction. What are the conditions for this to be accepted? Does it even deserve a place in the game?

Also, what is your single favorite feature in Vanilla for gameplay/realism purposes? I have yet to try a mod but I'm hearing good things about it. Naturally the developers' description is biased, so I wanted to poll you folks. Thanks!

I have had as many as 6 vassals in one game. I think some of it is your rating and some of it is just the factions attitude. At times there is just no way they will agree to anything. The sure thing is that they need to be down to three or less provinces. Having a high trust rating is a big part and their view of you as well. If you really want one you may have to make them like you even if you are at war. They go to war when they love and adore you then you make the demand…Usually when they offer peace you may have a chance. France would fold for most factions except the English. The Moors often will also.

I have also found that the faction has to have a way out. They can't be surrounded. But not all the time. One time I made the French vassels and the were at Paris and I owned all the surrounding territories. I was playing the English.

Never managed it either, though I did try it every time I could (H/H). Even tried bribing them with lots of small amounts of $ to butter them up, all to no avail. I am normally not all that chivalrous however.

Am now playing LTC, and it's much easier to be trustworthy (just maintain alliances), and so is much easier to get vassals. Much more realistic in that way I think.

In unmodded M2TW, getting the AI to become your vassal is more difficult due to the requirement that all their regions must border yours. In VM I modded it so that you only have to border 1 of their regions to satisfy the requirements (and of course have a huge army at their doorstep and generally be vastly more powerful than they are - the easiest way of doing that is to build and man a fort in their regions)

The benefits of ahving a vassal is that you get a large chunk of their rest treasury when they end their turn and of course alliance + military access.