This is a better question than you perhaps realize.
In your post you don't offer what the purpose is of finding an "easier way" to read DFDRs and CVRs but if I read between the lines this is a maintenance function for periodic testing and validation of the equipment.
First, there's a very good explanation of flight data recording here
, and how flight data recording works, in detail, here.
There are significant benefits, and liabilities, associated with flight data recording. Both are very powerful technical, economic and legal aspects of any recording work.
There are two reasons I can think of that prevent the "easy" reading of flight data and cockpit voice recorders.
First, the equipment, which includes DFDAUs (of which there is an example here
), the equipment and the software for reading recorders and the documentation supporting the design and installation of the recording equipment, are all proprietary, highly regulated and very expensive to develop.
Recording equipment and software are uniquely tailored to specific manufacturers of aircraft and to specific aircraft themselves. Both equipment and software are often tailored to the individual aircraft system and the FDR, CVR and QAR installations. The technology and more importantly the regulatory environment is relatively young, (perhaps two decades old) and older aircraft are much more difficult to equip than aircraft being manufactured today.
Regardless of type, such installations are subject to regulatory approval and certification requirements which vary among countries, again for different aircraft and different combinations of recording and reading equipment.
These requirements place very high premiums on the software and the equipment doing the recording and the reading of data. Manufacturers of aircraft and of recording equipment retain very tight control and broad rights to both the equipment and the software that runs it.
Corporations therefore very carefully guard the access to such software. As you're probably aware both the equipment and the software is extremely expensive. These are some reasons why.
Also, reading and interpreting flight data and interpreting CVR recordings is a complex process requiring training and experience. Flight data can only tell "what" but not "why". When interpreting the question "why?", flight safety work must remain as neutral as possible, ignoring legal, political and other pressures from elements which would benefit from one interpretation over another. It is not a straightforward process even though many believe that it is.
This leads us to the second reason which is unrelated to the first and is more complex.
Flight data was initially created (by an Australian and later the British), to find out what happened in an accident. Much later, such data is used as a preventative tool in programs such as "FOQA
There are many interested parties in any accident investigation and each will have a preferred interpretation of both flight and voice recordings. As evidenced by what is probably the longest thread on one topic in PPRuNe's history, the AF447 recorders still could not settle a number of interpretations of how and why the accident occurred. Legal, social, economic, political and technical pressures in such interpretive activities are enormous and do weigh heavily on outcomes.
The use of flight data to prosecute flight crews is another reason why flight data is not available to just anyone.
This is a very quick, short response about why there is no software or reading equipment commercially available for the purposes of reading FDRs, CVRs and QARs in the same way that MS Office is available.
There is a lot of information available on the web regarding how data recording works. Some knowledge of how this is done and why would go a long way to understanding why "just listening to the CVR" cannot be done. I hope this helps a bit in understanding why.