Sorry to be so late in jumping on to this bandwagon but have enjoyed the outline to the fictional account by given by Lady H and the valid responses of Demetrios and Pectinarius. I would make a number of comments as follows:
(i) The main problem was not that the Imperial Roman administration were stupid in not just accepting 1/2 the Iceni lands as willed to Nero and Rome by Prasutagus when he died. In fact the opposite was the case - Prasutagus totally misunderstood the concept of a client kingdom. He ruled at the behest of the Imperial administration with Roman support as a Roman ally. On his death, the Romans would either extend the client arrangement(if thought to be appropriate) by nominating a kinsman of Prasutagus to be the new client monarch OR the territory of the client kingdom would be absorbed into the Province. Prasutagus unfortunately instigated the revolt by leaving 1/4 of the territory, that was not his but legitimate Roman territory, to each of his daughters.
(ii) Boudicca did not move towards Lindum to engage Roman forces. Legio IX was commanded by the impetuous Petillius Cerealis (future relative of the future Emperor Vespasian). He proceeded south with a legionary vexillation and cavalry, probably to try and save Camulodunum but the infantry was cut to pieces. He skulked back to Lindum with cavalry support and took no further part in putting down the revolt. Note that, unlike the unfortunate Posthumous of Legio II Augusta, he did not fall on his sword but actually returned to Britannia as Governor some 10 years later (which can only be through the patronage of the now Emperor Vespasian).
(iii) there is no valid evidence in extant writings or archaeologically to suggest that the Boudicca revolt was supported by any tribes in the Province other than the Iceni and the Trinovantes (whose land around Camulodunum had been forcibly taken by veterans for the formation of the colonia that was placed there (indeed, the Catuvellauni who were located to the west and south-west of the Iceni and Trinovantes had started to become Romanised as evidenced by the foundation of Verulamium. The tribal elite of the Catuvellauni had abandoned their Iron-age Prae Wood site [and probably Wheathampstead also] to become "city-dwellers", the city having undoubtedly been planned, laid out and built by military surveyors and engineers. The fact that they had taken up Roman ways ensured their destruction by the anti-Roman forces of Boudicca.
(iv) Pectinarius made some excellent points about Posthumous and Legio II but perhaps an additional point might be made here. Whilst the tribes in the Province did not join the Iceni and Trinovantes in open revolt, none of the Welsh tribal lands were occupied at this time, of which the Silures in SE Wales were by far the toughest and most troublesome. It might be expected that the Druids would seek support from the unconquered tribes and maybe Posthumous felt he could not leave the south-west and west vulnerable by wholesale removal of troops to support Suetonius and that a vexillation in column of march could end up in the same disastrous situation that had befallen Cerialis/Legio IX.
(v) finally, whilst Seutonius pursued the defeated Iceni and Trinovantes to extremes, it was the Procurator of the Province, Julius Classicianus, who appealed to Rome for his removal so that the process of healing could begin. The recall of Seutonius ended the war so that progressive Romanisation could be further embedded even in the offending tribal areas.