Why wasn't it built as a classic "trumpet", with the exit slip off the southbound A1 to the north of the bridge, so it could merge with the northbound exit and avoid that T-junction? Okay, so it's only a B-road - but it is the main route into Stamford from the south, and just to the east is Burghley House. It can get very busy here when the Horse Trials or other events are on, and that T-junction won't help with traffic flow.
Having driven through it, I was struck by the very tight bends on the sliproads, especially joining the A1 southbound. Instead of following the line of the old road into a nice long sliproad to help merge into the 70mph stream, the access to the A1 south does a viscious right-left S-bend before dumping you almost immediately onto the main carriageway, requiring some very rapid acceleration. For a new junction, it's pretty dire!