Small berries are not always a good thing in red grapes. In the last week vineyards with very small berries have been slow to change colour. This would indicate the vines have been under water stress in the lead up to veraison, and their leaves are not functioning well. This late colouring fruit may cause uneven ripeness at harvest.
Pictured is a block of Shiraz (above) at Willunga on heavy Biscay Soil is only 15% veraison this week - neighbouring vineyards with larger berries and a healthy have raced ahead to be 90% veraison.