We're beaten over the head with the fact that the Nexus is so addictive that you'll never want to leave it (Guinan), and if you do, you'll do anything to get back (Soran). And yet Picard and Kirk find it very easy to leave and never come back. This is the biggest flaw of all in the film.
Well, okay, but it's also quite easily explained away - Picard and Kirk made conscious decisions to leave the Nexus, whereas Guinan and Soran were ripped out, and the trauma of the latter method is incomparably worse than the former process. (But
they wouldn't know that; they'd only know how awful it was for
them.) One could, if one were so inclined, make a crude analogy to different forms of sex, which I won't spell out any further. Fan apologism? Sure, guilty as charged... and it's a finding I can live with.