TL;DR: I agree with Donald X. that Empires and Intrigue 2E sound like the best bets based on your criteria.
Here's a more detailed answer if you want:
I don't have a particular favorite playstyle. I like to trash down to a svelte deck where I get the same strong hand every time. I like to build an endless chain and draw 20 cards on a turn. I like to try weird things with Tacticians or Gardens just because, and get a thrill when they work and have a laugh when they blow up on me.
This screams Empires to me. Not only are there different cards that support different kinds of strategies, the huge thing is the landmarks. Some of these can create entirely different ways to play the game. So, if you like a variety of different playstyles, Empires for sure.
I appreciate what I'd call "reactive player interaction." I like the artifacts because how many flagbearers you need isn't dependent on some engine calculation but based on what your opponents are doing. I don't like the witch because it makes your opponent take curses, but because when my opponent buys one I'm left with an interesting decision - do I get a chapel to reverse the damage? Do I buy two and outrace him through the curse pile? Buy a cellar and just cycle over the garbage? Remodel them into Estates? I like games better when they contain reactive decisions like this.
I think both Empires and Intrigue 2e fit here (although a lot of expansions do really well on this count, Prosperity for example has a lot of non-attack player interaction). Gathering and split piles in Empires can lead to a push and pull between players as can some of the landmarks with limited VP available. Intrigue's attacks have variable modes that can allow for more interaction than more straightforward attacks, and things like lurker can create scenarios like artifacts do.
I tend to play with many people who will only play a few times, rather than the same people over and over. So accessibility is valuable to me.
So, I personally don't think Empires is as complicated as Adventures or Nocturne, but it is on the more complicated end of things. But, if Adventures is of an acceptable level enough that you've already bought it, then I wouldn't worry too much. Intrigue definitely has more straightforward effects on its cards, but one thing to think about is that its emphasis on variable effects can lead to some analysis paralysis for some players. If accessibility is really important, I'd push more towards Seaside or Hinterlands.
I like boards that offer you a few different ways to play them, rather than boards that scream a specific strategy and all the players are trying to see who can get that extra inch out of the engine.
Again, this screams Empires to me. I think Empires supports divergent strategies maybe more than any other set. Landmarks give different paths to victory, but so do Castles and most of the victory token cards. I've played multiplayer games with lots of Empires cards where everyone was taking a different strategy to scoring points.