Although showing visual hints is acceptable, never should a logo show exactly what it’s representing; doing this shows ignorance on the part of the designer. A logo should have a connection to what it’s representing, but not entirely reveal what that thing is; this gives it the quality of being an invitation to discover exactly what’s lying just around the bend.
If the whole brand is being shown in the logo this reveals that a designer is unskilled in visual communication. If he or she can’t show an impression of something and is only able to portray the thing itself, can’t everyone else do that as well? Business isn’t about same-ness. It’s about distinction.
But the biggest failure is the disservice this sort of design does to a brand. Besides cheapening the whole brand for the reasons mentioned above, it gives the potential customer no incentive to search out the brand more. If everything is revealed upfront, why look any further than the logo?
The logo isn’t designed to do everything; it’s a visual element that should be created to act as a leading line from point A (introduction to a brand) to point B (becoming acquainted with the brand).
Dualogo 