Allow selection of multiple controls in the the tab order list.
Select a group of controls in the designer, right click and auto order (left to right, top to bottom by position). This would be a quick way to order a group of controls. If not this granularity allow auto order of all controls based on position.
When adding controls to a form, add them to the bottom of the tab order instead of the top (Currently new controls are added to the top of the tab order). I usually design (and) I think most from top to bottom. After adding 50 controls to have to reverse the order is time consuming.