Both great scenarios, though, I found I enjoyed Bahssikava more. Definitely would not recommend singleton if you are playing legitimately (unless you are playing as a very high level jack-of-all-trades) as it can be extremely difficult, but I enjoyed the various options for a party composed of only Slith. The things I enjoyed specifically were the cutscenes, the well thought-out plot, and the challenging combat. Legare's magic river split was magnificent!
I, too am very disappointed we will not complete this trilogy. I can see why people think the ending is rather dull, unless you have a vast imagination. Overall, both scenarios were great, though as I said before, my poor slith went all that way only to be turned away in the end. I would kill if even bits of the plot you had in mind be released assuming you're never going to finish it. Best scenarios I've ever played, and most likely will ever play!