In MLB sabermetrics they use positional adjustments to account for difference between an average player at one position vs another. Using these the most "important" positions in terms of saving runs are in order (the numbers are just relative numbers..)
1) C (12.5)
2) SS (7.5)
3) CF/2B/3B (2.5)
4) LF/RF (-7.5)
5) 1B (-12.5)
Now of course this is for MLB but in general if your team has other kids who can at least catch a flyball and a throw to them at 1B then if you have a good (or even average) SS or Catcher moving them somewhere else is probably not a good idea if the replacement is below average (if you are looking at defense alone). Small differences at those positions are magnified.
All positions are important, some more than others. Also all positions are difficult to learn if you want to play them well but some are more difficult...sorry.
I tell my DD, who plays 1B when not pitching, that 1B is the easiest position out there. I tell other parents that too. And as you get on a better and better team, the throws to you are more on target and it becomes even easier.
Some parents I know feel it's an honor for their kid to play 1B. It might be, in that it means they want your bat in the lineup.