Yes, it was, but that's not because it was a poor side.
It had recently beaten a West Indian side 3-0 which was quite conceivably the best of all-time.
Including as it did, the great all-rounder John Goddard; the three Ws; Sobers and Gibbs at the start of their careers; Ramadhin and Valentine; and Wesley Winfield Hall, the great seamer.
The fact that Australia's modest 58\59 side crushed England 4-0 was as bizarre as that England won that series 3-0.
In the 40s we were still suffering from the War; with the like of Hedley Verity tragically killed in battle, and several players (Godfrey Evans, Les Ames, Gubby Allen) having to fit cricket around uniform duties, it wasn't much of a surpise. The only authentic cricket (against sides we wouldn't be expected to beat heavily) was against the '48 Invincibles, whose 4-0 triumph wasn't exactly a surprise - I don't think many would have competed with them.
WRT to '60s, once again, we were good, but so many of the players didn't produce Ashes and Wisden Trophy victories.
I hardly think a side including Dexter, Graveney, Boycott, Barrington, Edrich, Snow, Underwood and the like could be described as shabby. West Indies had some phenomenal players in the '60s and not once did Australia win The Ashes by a large margin (both away series were drawn, and in both home series a crucial Test was lost by a small margin, most famously the Benaud-around-the-wicket match). By 1968 the tide had turned and Underwood and D'Oliveira lit up a dismal summer at the last possible minute.
Personally I don't think Harmison and the like are fit to lace Snow, Willis and co's boots. Yet, anyway.