Meta-analysis of LARP costume

You show up to a LARP. Let's say that there are a dozen players. I've probably covered this before ( but a quick glance through recent posts doesn't seem to indicate that), but I typically find that this group of players will have originally come from the five standard pools of potential players...

1. Tabletop gamers - I guess this is the direction I've predominately come from. These tend to be players looking for a more immersive experience, or have moved away from games dominated by a GM when they've had too many scenes where their interpretation of events have not meshed with other players or the GM. Tabletop gamers typically love the rules of the game. (I've seen both of these)
2. Computer gamers - There is only so much that you can do in a computer/console game. Sure, they seem to be improving and expanding with every new release, but sometimes you just want to go outside the scope of the game. LARP has a more flexible membrane around its creative space, it also provides a bit more of a social experience and a bit of exercise. 
3. Theatre performers - While these players really get into character, often with crazy accents and mannerisms, they often pay little heed to the rules that govern the game. They typically don't deliberately cheat, but they feel more comfortable when there are less rules, and often feel like they've failed when the rules come into play.    
4. Re-enactors - Are used to authentic arms and armour. They may not know so much about the rules or the fantasy, and they'll have specific thoughts about the way things were done in a historical period approximating the setting. As a resource of immersive knowledge they can be great.  
5. Cosplayers - More recently I've seen LARPs draw numbers from the cosplay circuit. These players tend to be typified by awesome costumes, and a degree of characterisation, but quite often the characters they play will be thinly veiled reproductions of existing characters from anime or some other source, and the costumes will be far more flamboyant than functional.

The sixth group from which players come is other LARPs.  

(Yes,I admit that these categorisations are gross generalities...used for dramatic impact).

Let's look at the way those 12 players are dressed, given that we might have specified that the setting is generic fantasy and that costumes were expected. I'd suggest that...

• One or two of those players probably still won't have shown up in a costume. 
• Three or four might be dressed in simple costumes, maybe street clothes with a tunic over the top, they could have walked off a cheap fantasy movie production, not overly elaborate but passable. (Generic "dark-ages/middle-ages" European)
• Two or three of those players would be dressed in armour of some type, probably leather, but someone may have gone over the top with full plate armour. (Such armour again tends to focus around the generic "dark-ages/middle-ages" European epoch)
• One or two players will be in a good/elaborate costume but it will not fit everyone else's epoch. They might be dressed for a later period (steampunk/victoriana has been more common lately), or might be dressed for a very different cultural paradigm (the inevitable ninja or samurai in an otherwise European setting).
• Then you'll get the cluster of players who want to be monsters. They LARP to get away from humanity as much as possible for a few hours. They may wear masks or make-up to complete their look.

Is it a good idea to allow all these variations in a single game? Will it drive away certain players it you put limitations here? (Are there certain types of players who you'd actually like to push away in this passive manner?)

Not addressing this at all might considered a "fruitful void" for exploration of character, and fleshing out the world of the LARP through the costumes, accents and mannerisms of the players as they portray their roles. Personally, I'd rather hook these concepts into the game at a story level, and make these player choices more integral to things.

So, the world I'm proposing for this LARP is generic fantasy. A great kingdom suffered a magical cataclysm some time ago, a mystical effect sealed off the region until a specific time period or astronomical alignment occurred. Life has gone on in the rest of the world, and now that the land has been unlocked from the mystical seal it is nothing but wilderness with a few scattered ruins at the locations where the major cities of the past once stood. In eight directions around the "fallen lands" exist the cultures that once traded with the lost kingdom. A character's starting costume indicated which of those lands they hail from, as each culture has sent adventures to explore the empty land and reclaim parts of it for themselves.

North – Viking/Russian (Icy Waste)
NE – Mongol/Chinese (Grasslands)
East – Japanese (Forested Islands)
SE – Siamese (Humid Jungles)
South – Indian (Hot Desert)
SW – Arabic (Rocky Desert)
West – Germanic/Slavic (Mountains)
NW – Celtic/Western European (Moors and Rocky Crags)

3 European inspired "cultures", 4 Asian inspired cultures (if we count a culture inspired by subcontinental India as "Asian"). I'm also seeing 4 great mystic portals at the cardinal points of the old kingdom, the seal was based around them, and now that they've done their job, they work as portals to other more exotic cultures (perhaps Meso-American inspired, Polynesian, Indigenous, or ancient Greek/Roman/Egyptian). 

Note that these assorted lands that once bordered the great kingdom will not be monocultures. There will be a variety of cultural backgrounds that make them up, but they will have a propensity toward producing certain types of adventurer due to the skills considered important in their daily lives.

I'm hoping that this is a blend that will get players thinking about the costumes their characters wear, without totally eliminating certain styles of outfit.