The changes made to this edition of GH make it a much better game than the last few efforts. The ability to play in a band with any combination of instruments (4 guitarists; 2 bassists and 2 drummers etc) is a welcome addition... Now the wife and I no longer have to fight over who gets to play guitar and who's "stuck" playing bass. Separate star power meters and the new "band moment" chords (essentially star power for the whole band) is a nice touch also.
Career mode also has some nice additions. Every song you play now has "challenges" attached to them allowing you to get an extra 1-3 stars for completion. Along with an elusive sixth star for perfecting a song, you are now be rated 1-9 stars on songs. Challenges consist of things such as "Score XXX points with star power activated," or "have a XXX note streak." With different challenges for different instruments, it really makes you WANT to play each instrument instead of just guitar.
Career gameplay still seems to lack when compared to Rock Band. it's a similar layout to GHIII, forcing you to gain a certain number of stars on single songs to open a new venue... No "setlists" with random or player-selected songs. It works, but it does seem to make the GH series feel more like "just playing songs," instead of playing in a band (what band plays one song at a time?)
The track list this year is disappointing (subject to personal taste.) Of the 85 songs listed, only a third are songs I really enjoy playing (there are some good "sleeper" songs, as usual... Ones you've never heard of but love after playing.) Trying to curb this, GHWT downloads work with GH5 and Activision is allowing you to import your GHWT songs for a mere $3.50. What they don't tell you is that due to licensing issues, only 35 songs from WT actually import. Combined with the still-limited DLC, the limited number of songs on GH5 make it STILL inferior to Rock Band... but it's a change in the right direction.