I don't know DS's IQ, nor is he a member of Mensa. He was doing the sort of stuff that Saffron was doing and more, though. I could bore amaze you with anecdotes but I suspect that Worra et al are entrenched in their "no such thing as a gifted preschooler" belief so it's probably a waste of time and would almost certainly out me to anyone who knows us.
I do agree that the gifted label is overused and makes it very difficult for parents with gifted children - I mean really gifted children rather than those who can recite Twinkle twinkle correctly :) I suppose it's the same as pseudo-allergies making it hard for parents whose children have real, life-threatening allergies to be taken seriously.
I actually do agree with the less structure, more play argument. I'm a childminder and I see many bright children who are pushed so hard they have no idea what to do when left to make their own choices. It sets my teeth on edge when a parent tells me their child must practice their handwriting through the holidays, or do extra maths. I'm all for child-led learning through play at this age.
Often, a child will arrive at my house with a workbook "in case she gets bored". I make it very clear that we do what the child wants to do at my house and, to give them credit, most parents are happy with this.
I have never had a child who wanted to do their workbook :) They all, without exception, leave it to gather dust while they get on with the serious business of playing.
The things my son struggled with were his social skills, his physical skills and learning to switch off and relax. These are all very common problems with gifted children and learning through play really helped him develop these skills. He did often want to do a page of maths - note: he wanted to - and I would let him, but I also made time for the equally important skills he struggled with. Fine motor skills were developed with art, with games like Scissors Paper Stone, with maze games. We also used climbing equipment to help with his co-ordination. Impossible not to develop social skills in a childminder's house 
Play and relaxation are vital for all children. I feel very strongly that they should take precedence over any structured learning, especially in the Early Years.