A lot of people can relate- I find myself noting other player's and their RP interest along with my own. Are they attentive during our roleplay?- is the topic/flow of theme something they like? I suppose this is because one of my characters tries to pay attention to characters in that way, I end up doing it with players. This somewhat leads me in attempting a broader scope of roleplay. Politics, religious talks, teaching, learning, idle living roleplay, occasional mild combat rp.. If someone wants to roleplay, I usually soak up to any topic/type that I feel we both seem to like. If I get sluggish in one topic, I ease into the other. ..Sometimes the rp consists of lots of words on my end.. This leads into revitalizing rp interest in one way: Broaden your comfort zone. You're only practiced in political rp and playing a human- yet find that rp is a bit stale? You only roleplay with a certain group and they're not online? Give your character a side-interest- hobby, maybe? Brewing, traveling, writing, shooting targets with arrows, practicing short blades, etc. Try a new race and see if you can find a new roleplayer. Maybe give our races some love- I know humans are easy to play, but different cultures can be interesting. In some sense, I don't mean create new characters to fit new areas of roleplay only. Maybe find your current character has more interests than you thought. This is probably one of the more drastic methods of revitalizing RP interest, changing what you usually did before- but only if it's something you believe the character can do and can handle, along with your like of it.
Simple things could be:
Give your character a new goal. Finish their current goals. .. - Slowly set goals that should be tangible and something they can probably accomplish in the future. Help someone else finish their goals, etc. (Sometimes characters reach their end goals early with death/they actually complete it. Find another goal or finish the story. No use keeping a hanging character loosely around unless you give them more of a purpose.)
Find a new player to roleplay with. A fresh face, a new page. (Sometimes lack of rp interest comes from your rp partners/group taking breaks.)
Sometimes, roleplaying by yourself gives more interest to the character. Where you're the one creating the moves, the short story, etc.
(Creationary mayyy not be a word). This is a hard one. But one is not better than the other. A practiced roleplayer should learn both methods, create and react. Realized early on I'm comfortable with both, and it's taking me time to realize that it's not easy to balance. By creating roleplay, you're making a new sandbox or pathway to pursue for your character and other characters. This generates more roleplay for anyone catching interest, including yourself. If you find yourself lacking in creating roleplay, give your character a goal to pursue. Take an initiative in creating roleplay. It could be going from training their new squire to use shields to signing up for brewing lessons. Writing a journal on a topic to pursing another character for some reason. For the more ambitious, it could be creating the 12th Kingdom in Altera (We have lots, who's counting?), or something more grim and memorable. A player should indeed strive to create dynamic roleplay if they have that ability and want to pursue it. Being solely reactionary will definitely wane interest.
It isn't bad to be solely reactionary if the character was supposed to be background noise, or if you're just here for some idle roleplay. Some players create background characters to have light roleplay or to support other characters. You just most likely lose interest faster than a character that has short goals and long ones that've been given a bit of time and thought into them. Handing background noise characters their own goals give them a bit more life. They may regularly do idle, reactionary roleplay, but once in a while have small bursts of serious roleplay to finish their goals. It's alright if not all your roleplays have your character learning something amazing, pursuing something grand or destroying something. It's alright if it takes time to get there.
I have more thoughts, but my energy is fused. I saw a few other questions that could use discussion, too. May come back later to elaborate/add. ~