Some discussion fragments I’ve heard often enough recently. Most of them can be found in the comments of James Maliszewski’s An Opportunity Missed article or in Daniel Proctor’s Evolution of the Old-School Renaissance, for example.
Space: “New products need a lot of pages.” New products have backstories, NPC motivations, and big stat-blocks. Some people say these elements are easy to drop. The counter argument is that it takes time to filter the information, it affords looking things up instead of making them up, and you’re paying for the material you’re not using. Nobody is contesting awesome art, good paper quality, beautiful maps, and cool encounters.
Evolution: “Not all change is an improvement but all change builds a market.” Everybody likes improvement. Some people say that the changes made are improvements. The counter argument is that out of print games are not obsolete – good fun stays good fun. Some people say that change is what constitues a living system and allows active support. The counter argument is that companies might like to provide support in order to make a living, but players don’t necessarily need it, specially if they embrace a do-it-yourself attitude.
There are other elements that are much less contested (location based design, adventure paths, options/optmizing minigames), but they’re usually much less controversial.