Currently writing up some area control mechanics, but the theme has not come to me as of yet. Right now, the mechanics have players playing different factions with different win conditions that battle it out for control of settlements/locations. In ur opinion, what is the best theme that can really draw the player in and immerse them into the game?
What theme best fits an area control style game?
Your description is so vague that almost any theme could apply. What makes your game different from other area control offerings? If you can identify a unique selling point, maybe it will be easier to pick a theme that emphasises that point.
Zombies VS Vikings VS Pirates.
Also it must use legacy mechanics.
Can't go wrong with that.
Area of influence mechanic you mean? Something akin to a tabletop version of Battlefield like parking your pieces/models within a certain distance of the objective to hold it type deal or am I misreading this entirely?
When you say control mechanic I'm thinking the type of mechanic that represents the ability to get orders and commands through your troops ala Warmaster, Blitzkrieg commander style games. Most civil war games have something similar.
I need to know what you're looking for specifically.
Also it must use legacy mechanics.
Can't go wrong with that.
That's the ULTIMATE GAME! lol
Spheres of influence within the UN (& how they negotiate & coordinate to combat the zombie Viking pirates that are causing havoc on the international shipping routes)
Famine. Players control warlords competing to steal humanitarian aid intended for the various areas.
"Then there's Nourish A Child, Shoe A Child, Bespectacle A Child, umm, One Laptop Per Child Soldier . . . which, unfortunately, soon became One Thousand Laptops Per Warlord."
-- Cecil Tunt, Archer
As others have said, you can cram any theme on there since you've been so vague.
Pick a theme you know well and enjoy working with.
Putting a theme in that you don't care about will make the game suck since you wont care to really fit it in right.
Also slapping a theme on as an afterthought, rather than making it an integrated part of the game, will make it incongruent and communicate bad information (ie it'll tell the player "expect these thematic elements" and then never follow through)
Make a game which works, make it abstract - some of my favorite board games are not the ones with clever themes but the ones which play well.
"Why do I have to make all these little tokens move through 'hidden' pipes to invade different coloured tiles?" - "to win the game".
[edit]
Sorry, I didn't read the Zombies vs Vikings vs Pirates suggestion or I'd have gone with that. Oh but you forgot robot ninja monkeys.
Depends on how much you want to do with the theme.
Should there be a story behind it, or is it just flavour?
Either way it could be nice to go with a theme thats not often used, so your game will stand out. And of course you should personally like the theme.
Some suggestions from the top of my head that would work with factions with different win conditions fighting for controll of areas:
-classic mobsters.
-gang warfare.
-greek city states.
-various aliens fighting for planets.
-medieval barons.
-highland tribes.
-native american tribes.
Also it must use legacy mechanics.
Can't go wrong with that.
You missed the key selling ingredient. Cthulhu.
I agree with the comments that a theme is not a requirement. If there is something in your mechanics that clearly ties into a theme, then it's great to have one. But there are perfectly good games that don't bother. If the theme is just tacked on as an afterthought, that will show through and will be worse than not having one.
So, what's unusual about your mechanic?