If you want him to be able to write creatively and imaginatively when he is 7, then encourage him to do lots of imaginative play now.
If you want him to develop a broad and interesting vocabulary, then read to him, enjoy exciting and fun books together (read by you) with lots of pictures.
If you want him to have good general knowledge to broaden his understanding of the world, help him to have lots of things to write about, then give him lots of experiences - playing in the mud, swinging on a tree branch, cuddling a kitten.
If you want him to be a scientist then expose him to science - floating and sinking, plants, swings, mud, bubbles, playdough, paint, cooking etc.
If you want him to have good fine motor skills, then give him things to do which use his fingers - playdough, lego, colouring, handling small toys, rolling and baking biscuits, playing in the sand, threading beads.
If you want him to develop a good understanding of number then use number in everyday life - cooking, weighing, money, counting plates on table, teddies on the bed etc. and develop their broader understanding of maths - volume (water play) weights (cooking) time, larger than smaller than etc etc.
In other words if you want to develop your child's intelligence, then develop the whole child, not just phonics and numeracy. That is why the nursery has the curriculum it does