To be honest, I don't think Barney as a character would be able to sustain his own show.
That's because that's exactly what it is. We already know the endgame. Marshall and Lily continue to be parents, Robin and Barney get married, and Ted meets the mother. Ted has to do nothing but be at that spot because we all know now that that's where he'll meet her. The only characters that need to move forward are Barney and Robin, which is why they've become the center of focus, because the other characters literally have nothing to do. At least now we saw Marshall is involved in a big case, but the impact of that case on everyone is yet to be seen. But the big question now is not so much how does Ted meet the mother, but rather how do we get to the wedding?
And speaking of Smallville, they had an awesome second to last season, but once they knew the end was coming, they decided to spend the season looking back at the past and bringing back old guests, instead of creating a compelling arc to drive the entire season forward. HIMYM has sort of done the same with all the Ted/Robin and Barney/Robin stuff.