I just thought of something. You could develop a tank of a character, but give him high CHA and overburden him with social skills as well, thus causing immense ructions when he not only dominates the battlefield - he also tends to walk away with the pretty barmaid afterwards. and all he has to do is just smile and say "Thank you very much" a lot ... even if that's the only thing he knows in the language.
Games Masters, and this bit is for you, if it looks like you've got one character dominating the game's proceedings, don't just nerf the guy or find ways to sideline the player. Just aim for a little balance between how long the characters get to shine.
Not all the stories in Stargate were about Teal'c - it was an ensemble cast, and even the minor B-team characters got their chance to shine. Once a year on CSI: Crime Scene Investigation, the Lab Rats got their show segment to themselves, with the A players occasionally swooping in to mess things up or to remind them that they are on a schedule with that Trace report ...
And while there were some amazing episodes of Next Gen, DS9 and even Voyager and Enterprise themed around one character, pretty much all of the post-87 24th century Star Trek was an ensemble cast, with one or another character getting to make the decisive action that saves the day (unlike TOS, where it was pretty much Captain Kirk who'd save the day and get the girl, almost every single time).
So don't think like Doctor Who, where it's all about the Doctor, and his Companions are only there to have someone to explain to. Think of it like Babylon 5, where you'd have your A story - which could be about Sheridan and Delenn, or G'Kar and Londo - and then you might have your B story, where it would be about Lennier or Vir Cotto or Zack Allen. And sometimes the entire story might be A reel, and focus on someone other than Sheridan, such as Garibaldi.
As long as you understand that it's okay to have a focus on one character, because the story you're running is
about that character - but that focus can shift, expand, contract to a tiny point, blur or encompass the whole group at any time.
Keep it going, keep it shifting, and everyone will get their chance to shine even if, say, they aren't tanks or great seducers, or particularly good at anything skill wise. It's their courage and their willingness to jump in to danger feet first and eyes wide open that makes them Legends, not the numbers on their character sheets.
I should be doing this for Mongoose, for money, shouldn't I?