Re: A more realistic approach to away teams
David Gerrold entertained the idea of away teams as early as 1973, in his book The World of Star Trek. He proposed the first officer lead the team, with the captain staying on the bridge. Apparently he was able to push some of these ideas during TNG's first season. But as others have said, realism doesn't always equal effective drama. Your top-billed actor as captain is eventually going to grow tired of missing out on all the action scenes.
Gerrold, D.C. Fontana and Bob Justman all should have gotten co-creator credit on TNG. But the matter was settled privately.
"If I hadn't tried, the cost would have been my soul." - Admiral James T. Kirk, Star Trek III: The Search for Spock