Both plugins are useful however the last.fm plus plugin is complicated to support and has complicated options. They could be simplified for more casual users so it can suit both sets of demands.

In particular, the lastfm plugin could do with these features from lastfmplus, even for casual users

• support for tagging with maximum n genres
• support for "grouping" (major genre)

Suggested "Advanced" options

• Weighting stuff could be in advanced section.
• Mood, Occasion, Category, Country, City, Original Year, Decade

Should probably create subtasks for various components of this.