Hi A. C., Welcome to the Boards! You'll find plenty of fans of the Jason storyline here. Several of us rate it as among the very best of the entire series.
I agree that a lot of the Jason shows are more compelling than the Barnabas/Maggie kidnapping shows, and I'll give you my personal reason why. There was more scope IMO for dramatic tension between Jason and Liz, and Jason and the rest of the crew at the Big House, with the way Jason's scheme played out. Joan and Dennis had some tremendous confrontations and the material required Jason to be quite devious and think his way out of the various attempts by Liz to sabotage his plans. It felt as if the two were more evenly matched, and there was also the material from the responses by Carolyn, Roger, Vicki et al to the unfolding situation. With Barnabas, Maggie and Willie it was pretty much the three of them engaged in a war of nerves in which Barnabas' supernatural powers kept trumping the situation. There was certainly some fine writing AND thesping in this story but a lot of it also felt repetitive and less dynamic, over all, than the Jason scenario.
Another factor to consider is the shift in Burke's role during this time and the eventual [spoiler]writing Burke out of the show altogether. Presumably this was done because the writers felt that if Burke remained on the scene, he would sooner or later, in any remotely plausible scenario, have learned Barnabas' secret. Perhaps DC was also thinking of having a stronger romantic relationship between Barnabas and Vicki than was eventually the case--something more along the lines of the 1991 story. For this to happen, Burke had to go. It's significant that by the time Burke was written out, in, what October of '67?, it was obvious to all that Barnabas was here to stay.[/spoiler]
Just some thoughts. Again, welcome!
G.