The "funny" thing is that DXV himself has suggested a maximum limit of two events/landmarks in total per game, and he has also said elsewhere that he in fact recommends playing with two events in every game (pre-Empires).
I don't remember him making any such recommendation. I think he said something along the lines of, if you want to put two Events in every game, go for it; you can shuffle the Events separately from the other randomizers.
Would there be a problem if one included three events/landmarks in some games? I mean when it comes to balance? I'm sure there's a reason a maximum of two is recommended.
Just to keep the game from getting crazy complex. But if your group can handle complex, do whatever you like. When playing with my main group, we almost always put out three: either 2 Events and 1 Landmark or 1 Event and 2 Landmarks. It's a holdover from Empires playtesting.
You're right about the recommendation thing. I mean, he said it, but it wasn't in a public forum. I listed somewhere (I think it was on BGG) that I wondered if someone could recommend 50 kingdom cards that would be best to use to showcase as many interesting game mechanics as possible while keeping each element visible enough.
I was going to sing in an opera, and for stage performers, it's generally a lot of waiting in between different scenes, especially during rehearsals, so I collected some of my colleagues and put in Dominion games anywhere we got the time for them. Going to an island for these rehearsals and performances meant that I had somewhat limited space for game accessories in my bag, so I figured I wanted to use about 50 kingdom cards, and then some events.
Donald X. replied to me in a private e-mail message, saying that he recommended bringing all 20 (at the time) events, using two in every game. So we did, and it seemed like a perfect number, even though some of the players had never played Dominion before. I think I'll go for two combined events/landmarks per game in the Empires era, at least initially. Thanks for your feedback! It's greatly appreciated!