Collections subscripting operator [] and boxed C strings are life-savers. Instantiating obj-c object is always a pain cause the syntax is very verbose, expecially for NSString:

  NSString *s = [NSString stringWithCString:"hello" encoding:NSUTF8StringEncoding];
  NSString *s = @("hello");

it's 11 characters vs 67. Now what I really, really miss is the implementation of the NSString concatenation operator. stringWithFormat isn't always the answer nor appendString. Please forgive me if you find that my idea is silly:

  // String concatenation
  NSString *s = @+(@"hello ", @"world");

Or maybe some concise dictionary operators.

  NSDictionary *d1 = @{ @"first":@"Hello", @("second"):@"World" };
  NSDictionary *d2 = @{ @"third":@"Greetings" };
  
  NSDictionary *cd = @|(d1, d2); // Dictionary merge
  NSDictionary *id = @&(d1, d2); // Dictionary intersect
  NSDictionary *dd = @^(d1, d2); // Dictionary difference