I actually loved Jacob Kell as the villain. He was super badass, but in a non-brute sort of way. He was just so, so ridiculously overpowered.....I loved it. I just wish they wouldn't have portrayed Connor as a depressed emotional wreck and shell of himself, and Duncan as a depressed emo stalker. With the epicness of the two Highlanders teaming up, I wanted to see Connor portrayed as the confident badass he was in Highlander 1 and 3, and Duncan as the unbeatable problem solver of Season 3 and 4. And then STILL make Kell too strong for them. That would have been way more badass than the way they went.
Anyway, Endgame was an excellent story in theory that got shafted by weak execution.
Fun fact...... Jacob Kell is the only immortal to ever legitimately defeat Duncan MacLeod in a swordfight. (I mean established Duncan, not new-to-the-game Duncan).