The role of the vinyl mastering engineer is to optimize the signal to take account of all of the above deficiencies of the medium.
At the same time, the mastering engineer will endeavor to improve the overall sound, and match different tracks so that they sound as though they are part of the same album.
The sum total of all of this is sometimes a very complex process and an intermediate 'production master' tape is made which incorporates all of the corrective and creative mastering processes. The record can then be cut directly from this.
In the CD era it is unfortunate that many classic recordings from the age of vinyl have been transferred to CD using the production master optimized for vinyl, rather than going back to the original stereo mix.
The role of the vinyl mastering engineer is highly specialized. He or she does this work day in and day out, becoming more expert than anyone working in any other area of recording could possibly be.
The first time in a vinyl mastering studio, people tend to want to tell the mastering engineer how they want it. By the second time, they have realized that the vinyl mastering engineer knows best.