I am not a huge fan of dual pivot (DP) brakes but they may be a good upgrade for you. Did they replace the brake cables?
A 28th is a great start but if you need a little more a smaller chain ring may help but it will lower all your gears. What brand is your crankset? How many teeth on the smaller ring?
BTW nothing wrong with commuting on this depending on distance and your requirements. If you need to commute in all weather and need fenders or need racks a hybrid type bike may make a better commuter.
__________________
“One morning you wake up, the girl is gone, the bikes are gone, all that's left behind is a pair of old tires and a tube of tubular glue, all squeezed out"
Sugar "Kane" Kowalczyk