WESTFIELD — Visitors to the North Avenue train station parking lot will likely have noticed that renovations to the historic stationhouse have almost been completed. The building, which will soon play host to a long-awaited Mexican eatery and cocktail bar, has undergone extensive changes over the course of the past few years. Now that the construction barriers have come down, residents have taken to social media to express concerns that the renovations — which, among other additions, include new siding, windows and bump out areas — have gone too far.