Late Roman Army during the 5th century

[starman2012]

Aetius still managed to get enough troops to attack africa in 440,

There were just preparations; the attack was cancelled when the eastern contingent had to go home to deal with the Huns. Apparently the western force was far from adequate.

My best guess would be that the Huns were a cover while he restored the field armies to a point where he would not necessarily need the huns to maintain his power.

What was taking so long? He needed to Huns to return to power in 432 and still needed them in 439. And one can't use the loss of Africa and money as an excuse for that.

Also, in 436 and 437 the Burgundians were attacked - the first time Aetius had Attila send a force of huns, the second time he led a Roman Army to defeat and relocate them.

The Huns must've done the bulk of the work the first time.