Based on this list, I pulled Goodreads ratings for over 350 original Star Wars fiction releases and re-ranked them by the cube of the rating (expressed as a percentage) times the log of the number of raters.
By that metric, here are the 50 most popular Star Wars novels:
1. Timothy Zahn, The Last Command (Star Wars: The Thrawn Trilogy, #3) 2. Timothy Zahn, Dark Force Rising (Star Wars: The Thrawn Trilogy, #2) 3. Timothy Zahn, Heir to the Empire (Star Wars: The Thrawn Trilogy, #1) 4. Drew Karpyshyn, Path of Destruction (Star Wars: Darth Bane, #1) 5. Drew Karpyshyn, Dynasty of Evil (Star Wars: Darth Bane, #3) 6. Karen Traviss, True Colors (Star Wars: Republic Commando, #3) 7. Karen Traviss, Order 66 (Star Wars: Republic Commando, #4) 8. Karen Traviss, Hard Contact (Star Wars: Republic Commando, #1) 9. Karen Traviss, Triple Zero (Star Wars: Republic Commando, #2) 10. Drew Karpyshyn, Rule of Two (Star Wars: Darth Bane, #2) 11. Timothy Zahn, Vision of the Future (Star Wars: The Hand of Thrawn, #2) 12. Aaron Allston, Wraith Squadron (Star Wars: X-Wing, #5) 13. Timothy Zahn, Specter of the Past (Star Wars: The Hand of Thrawn, #1) 14. Michael A. Stackpole, I, Jedi 15. Karen Traviss, Sacrifice (Star Wars: Legacy of the Force, #5) 16. Michael A. Stackpole, Rogue Squadron (Star Wars: X-Wing, #1) 17. Aaron Allston, Iron Fist (Star Wars: X-Wing, #6) 18. Aaron Allston, Solo Command (Star Wars: X-Wing, #7) 19. Michael A. Stackpole, Wedge's Gamble (Star Wars: X-Wing, #2) 20. Matthew Stover, Traitor (Star Wars: The New Jedi Order, #13) 21. Karen Traviss, 501st 22. Michael A. Stackpole, The Bacta War (Star Wars: X-Wing, #4) 23. Timothy Zahn, Allegiance 24. Aaron Allston, Starfighters of Adumar (Star Wars: X-Wing, #9) 25. Troy Denning, Star by Star (Star Wars: The New Jedi Order, #9) 26. James Luceno, The Unifying Force (Star Wars: The New Jedi Order, #19) 27. James Luceno, Darth Plagueis 28. Troy Denning, Invincible (Star Wars: Legacy of the Force, #9) 29. Michael A. Stackpole, Isard's Revenge (Star Wars: X-Wing, #8) 30. Karen Traviss, Revelation (Star Wars: Legacy of the Force, #8) 31. Aaron Allston, Fury (Star Wars: Legacy of the Force, #7) 32. Troy Denning, Inferno (Star Wars: Legacy of the Force, #6) 33. Michael A. Stackpole, The Krytos Trap (Star Wars: X-Wing, #3) 34. Timothy Zahn, Survivor's Quest 35. Troy Denning, Abyss (Star Wars: Fate of the Jedi, #3) 36. Karen Traviss, Bloodlines (Star Wars: Legacy of the Force, #2) 37. A.C. Crispin, Rebel Dawn (Star Wars: The Han Solo Trilogy, #3) 38. Timothy Zahn, Outbound Flight 39. Aaron Allston, Outcast (Star Wars: Fate of the Jedi, #1) 40. Steve Perry, Shadows of the Empire 41. A.C. Crispin, The Hutt Gambit (Star Wars: The Han Solo Trilogy, #2) 42. A.C. Crispin, The Paradise Snare (Star Wars: The Han Solo Trilogy, #1) 43. Troy Denning, Apocalypse (Star Wars: Fate of the Jedi, #9) 44. Aaron Allston, Betrayal (Star Wars: Legacy of the Force, #1) 45. Aaron Allston, Backlash (Star Wars: Fate of the Jedi, #4) 46. Christie Golden, Allies (Star Wars: Fate of the Jedi, #5) 47. R.A. Salvatore, Vector Prime (Star Wars: The New Jedi Order, #1) 48. Timothy Zahn, Choices of One 49. Troy Denning, Vortex (Star Wars: Fate of the Jedi, #6) 50. Aaron Allston, Exile (Star Wars: Legacy of the Force, #4)