I felt the same about the Passione long E. Thinking about it, on most Pirastro strings I have used in the past the E has not been as good in sound or feel as the other three, with the exception of Evah Pirazzi (and way back, when they had Flexocor 91 and 92- the 91 E was great, and then they discontinued it or changed it
). I really like the Bel Canto extended E but, as you say, it's a bit thick compared to the other three. I don't mind thick strings per se- I really like the feel of Eps, but for me the relative thicknesses from G to E are better.
Would you consider a Bel Canto E with Jargar or Passione top three? Or are they too different?