^Not to mention, historically lane widening on urban highways (and urban rings) tends to draw in more automotive traffic even withough the additional car-oriented development.
The elevated HOV lane is a smart idea, and I think something that should be considered because commuting north on the S.E. expressway during the afternoon rush is just as backed up sometimes as the southbound commute due to the lane restriction.
I've said it before and I'll say it again, 24 needs to be widened from the route 495 cloverleaf to exit 12 (Galleria Mall and route 140). Three lanes (presumably-1 enter/exit lane, 1 cruising lane, and 1 passing lane) could help ease up the congested areas by exits 12, 13, and the merge from 495 south to 24 south (goes quickly from 4 lanes to 2). This is one case where it's far enough out of the urban fabric of Boston where it could benefit from the third lane... it even seems the overpasses are wide enough to accomodate the additional lane (maybe some foresight on the state's part?!).
Route 3 on the south shore could use an additional lane for a further distance, but I don't know how the residents will feel about that. I don't know enough about Northern and Western suburban highways (routes 3,9, 20, etc) to comment on their current states, but I hear they could use some work as well.
*Edit*
I just noticed that you have route 24 being changed to I-695... what's the logic behind this? I'm not going to argue until I hear your reasoning, because 24 does connect to I-195 and I-495 as well as I-93, which all run into I-95, but I'm not sure what the significance of the changing of names is. Remember, 24 does run into I-195, but it doesn't terminate there, it continues south of I-195 through Southern Fall River and into Tiverton and Portsmouth R.I. and abrubtly terminating at the junction with route RI-114... does this segment become I-695 as well, or does it become 24 once you intersect route I-195 (therefore meeting the last direct connection to I-95 to the South)?