I know this is an old thread, but here is some additional info:
Lower T-map is used to determine intercooler efficiency (charge temp) and help ECM determine things like spark advance and retard, and also is used to regulate boost as in wastegate control and overboost (wastegate stuck) conditions. Intake map is used to control boost, and also fuel as you need a good bit more fuel when under high boost(to keep combustion temps down). The MAF only knows air flow, not pressure. There are also other things these sensors are used for, like the boost gauge for one.