One specification notibly missing from almost every receiver on the market is the current carrying capability of its internal power bus. Furthermore, a 'standard' type reciever usually only provides a single input (bat) port dedicated to power input. As this port is generally a 'servo connector' type interface, it also is limited to the current carrying capability of that connector - somewhere in the neighborhood of around 2 amps. Many (especially newcomers to this hobby) don't realize that using this single input is not sufficient to properly power a full set of servos and other on-board periperals. Nor may they realize that they could get around that limitation by getting more power into RX through used and unused channel output ports.
I'd like to see the industry as a whole not only start to publish an RX power bus current specification, but also publish 'recommended limitations' to its 'standard' configuration.
Consider integrated units such as Spektrum's AR7200BX RX/FBL combo - I can see where someone who isn't 'in the know' regarding proper power distibution techniques could easily think they have a proper setup - when its more likely they do not.