My idea I posted a few years back, wow, is  that Xavier starts the school as more of a safe place for Mutants to  live.  Sort of like sanctuary or protective ground for them.  At this  point mutants would still be few and far between and not at all known in  the public.  So he opens the school for young mutants to get a regular  education where they wouldn't have to worry about their powers going off  in class.  Because most mutant powers show up during puberty the  majority of students would be teenagers or pre-teens.  He has no plans  to use them as soldiers, but he does train them to use their powers,  with precision, because their ability to use their powers will help them  control them better.
The whole X-Men team would be something they stumble into.  They go to  stop Magneto from destroying a military base, and Magneto reveals during  the fight that the military base has files on them all.  Xavier then  trains them to protect themselves in combat and how to work together as a  team and family and how to look out for each other, but still not as  soldiers.  There could even be a scene where one of the students asks  why they even bother still having class when such things as Sentinels  and Magnetos are happening.  Xavier could tell them the importance of an  education, including to help them with such things as Magneto and  Sentinels.  Just like in Buffy, where she and all of the town are  constantly attacked and they all still go on living and doing what has  to be done.  She still went to school and graduated.
They end up facing Magneto and his own school, the Brotherhood, and  Sentinels, and Mimic, and other mutants and menaces. Hank accidentally  mutates himself further into a furry blue mutant.  The uniforms idea  could come from Warren who like comic books, or it could be like  Ultimates where the suits are made to mask their identities and DNA and  such, or it could be school uniforms, or a way to help the humans see  the good mutants from the bad.
Season Two, the addition of more mutants from other nations.  Russia,  Africa, Canada, etc.  The original students (Jean, Scott, Warren, Bobby,  Hank) are still in school but are older, like seniors or juniors or  something.  Some new students would be younger but some are the same age  or slightly older.  Wolverine would be the only adult, and would be  brought in to sort of help train the team.  But the focus and purpose of  the school has switched from providing an education to mutants to  protection of mutants.  The X-Men team is now a team, and they are here  to make sure mutants are not harmed and gain equality.  While there are  still classes and students the school has now become a house for the  team mainly.  The team doesn't really wear uniforms anymore, besides  maybe Cyclops or Beast wearing a modified version.  Now they each wear  regular looking clothes that resemble their comic costumes, like  Wolverine wears a yellow tank top with black slash marks and blue jeans.   Later during season two Kitty Pryde joins and Sunfire leaves and  Thunderbird dies.  They end up facing Magneto again, Sabertooth,  Mystique and the new Brotherhood, and get a glimpse of the future and  what they have to prepare for.
So instead of the team getting together to be a heroic super team for  Xavier, its more like Xavier planned to make the Mansion a safe haven  for all mutants and humans, but instead it became a HQ for soldiers.   Something that could eat at Xavier more and more as time goes  on.
                          I imagined, in my idea for the show, it would take the Buffy/Angel/Smallvile/Burn Notice approach to the stories.  
One large story arc for one season, but each episode could have a smaller story  like how Burn Notice has a large over arcing plot about (for example)  him tracking down the guy who killed his spy friend, but at the same  time he works on smaller cases like a nurse hiring him to stop drug  dealers outside her office.
So season 1 could be about the public discovering mutants exist and  Magneto be the main villain (like how Buffy had one main villain per  season) as the larger picture.  But the smaller episodes could focus on  smaller stories, for example the team meeting Mimic.  He is a young  mutant who only shows his mutation around other mutants.  When he is  around them he mimics their powers without meaning to, but when he is  around normal humans he shows no signs of being different.  Or, in  season 2, the over arcing story would be Xavier turning his school into a  safe have and his team of students into protectors of those mutants  with the main bad guys maybe being the humans with their Senator Kellys  and their Sentinels.  But an individual episode could be about  Sabertooth showing up on Wolverine's birthday, kicking his butt and  killing Thunderbird and making the dangers of Xavier's plans all too  real for the young mutants.  Or another individual episode could be  about Juggernaut showing up, Xavier's bother and maybe show some of  Xavier's past.  But the larger theme of season 2 would be Senator  Kelly/fear of mutants/Sentinels/Friends of Humanity, but would also be  about the idea of Mutants expanding showing they are happening all  around the world and not just America.  Moira McTaggert would also join  the show as a non mutant human from Ireland.  Or in the midst of the  drama a fun holiday episode where the Mansion celebrates Christmas and  Chanukah.  Or a while back someone mentioned a summer vacation themed  episode with the mutants at the beach or something fun like that.
I would love the show to sort of be all about Charles Xavier and his  dream in a round about way.  The show would focus all on the team and  their lives but since Xavier set this whole thing up and into motion he  feels responsible for everything at every turn.  He wanted the school to  be a safe place for young mutants to learn and then go out into the  world as adults, during season 1 and 2 the school becomes a HQ for the  mutant soldier X-Men, and Xavier even feels responsible for Magneto's  actions.  Magneto would be a fun character to see in the show too, he is  a bad guy, his actions make mutants look bad at almost every turn, but  he has good reasons and motivations and truly feels he is right.  But  maybe if it wasn't for his actions during season 1 Xavier's job might be  easier.
Season 3, I would bring in Mr. Sinister, the Morlocks, and the Marauders  led by Gambit, and Mior (spelling?) island.  And maybe Government agent  Valarie Cooper who is trying to get the government to see the value of  mutants.  I guess the idea here would be showing the furthering of  mutations and the manipulation of mutants by those who wish to use them.   Although season 3 might be too soon for some of this.
Also in my idea, it would be like Heroes in that they are really normal  looking people, not superheroes.  And they don't really wear costumes.
My ideas for the show:
http://forums.superherohype.com/showthread.php?t=312192
Ways I would make the show less expensive would include having Beast use  an hologram projector a lot, same with Nightcrawler, and the Sentinels  are like the Cybermen on Doctor Who (lots of guys in robot costumes  acting menacing).