The best connection of the proposed site is at the northwestern corner. Not coincidentally, it's also the most prominent corner for visitors arriving by car. But, there are still serious unmet challenges to good pedestrian access and circulation.
Ideally, the retail in the north building would have Boylston St./Rte. 9 as its front. Barring that, getting to the north retail (E) from the northwest corner is as direct as it could be. A to D is a straight line. The walk along from D to E isn't short, but it promises to be a much more friendly path than it's northeast counterpart.
There is a substantial entrance at D. The entrance at D seems designed to catch the attention of drivers, but it provides a collateral benefit to pedestrians. A building front, with glass and doors, is much more hospitable to pedestrians than the building's back. Plus, there's no dumpster or loading dock along this side of the building. And, of course, pedestrians can enter at least one store right at D!
What's definitely not good is the sidewalk in front of David's (B). Currently, there is a very wide shoulder and a very wide grass berm between the sidewalk and traffic. When New England Development is done with its widening, the only thing between pedestrians and traffic will be a measly 2' shoulder. Again, New England Development is making things substantially worse for pedestrians. Pedestrians need more room than a bare-minimally ADA compliant 5' wide sidewalk and a tire-width shoulder.
Also unfortunate, there is no way to get directly from the northwest corner to the residental/retail building (F). A nice direct path would be along the Capital Grille property. All that's missing is a paved section at G and a crosswalk at H. Given how direct this path is, it's hard to imagine that people won't use it, even without a paved section or crosswalk.
Another option would be to provide a sidewalk on the west side of the main driveway (I) and a crosswalk across the residential/retail building's driveway (J). Because the sidewalk along B is so crummy and because the path along the Capital Grille is so much better, this is an much less attractive alternative.
What's to be done here?
Make the sidewalk in front of David's no worse than it is now. There should be an equally wide grass berm. While there's no way that the shoulder will be as wide, the developer should compensate with some street trees.
Make the connection along the Capital Grille building. A small section of sidewalk and a crosswalk will pay big dividends.