Neither the total watts advertising nor ACD full bandwith at low distortion point specs really tell you a lot either. Sure be nice if they used dBW instead.
It would be good if audiophile product manufacturers showed the specs as they used to publish them in the 1960's.
However, pro audio product manufacturers are not as reticent about the publishing of the real useful specs. QSC Audio is a good exemple. Apart from the specs which are published with the product features and in the owner's manual, on their website you can even read the figures in BTU/hr, for various power outputs, of Amplifier Heat Loss for several models.
As for the slew rate, which is not considered as important from a sound perspective, QSC does not publish it. However, Electro-Voice were publishing slew rate figures for their amplifiers in the 1990's.