What's a good expression for "too much information"?

Solution 1:

If someone 'provides too many details on something actually making it difficult to get the needed information out' a word that could be used is 'verbose'. This is an adjective which means too wordy or using too many words as in a write-up or a speaker addressing an audience.

Please see my comments below first.

My second offering: circumlocution (n.) - the use of unnecessary wordy and indirect language. The adjective is circumlocutory. An antonym of a circumlocutory expression would be a forthright expression.

Solution 2:

You could say information overload. That expression has found its way into some dictionaries. One of them (Collins) defines it as:

information overload (n.) the situation when someone has so much information that they are unable to deal with it

Another (CDO) says:

information overload (n.) a situation in which you receive too much information at one time and cannot think about it in a clear way

The phrase seems to have gained traction since the 1970s, and the phenomenon is discussed in some textbooks as well. Here's just one quote out of many:

Thus, the danger of “information overload” is real; if any user were to receive all, or even a significant fraction, of the total amount of data contained in the system, he would be hopelessly swamped. (from Strategic Appraisal: The Changing Role of Information in Warfare, Rand Corporation, 1999)

Solution 3:

When you supersaturate somebody with information beyond their immediate requirement it is translated into an information overload. You end up making a mess of the whole matter because the recipient probably will even lose whatever vague initial understanding of the subject they had.

This is almost a normal occurrence when a postgraduate science student is asked to teach science to an eighth or a ninth grader. It is indeed an innocent curse because the elder is after all trying to help out the kid but unfortunately ends up messing it up.