No, no, no, no, no, no, no, and NO.
Season five was not a good enough season to end the show. In fact I consider it only a tad stronger than season four overall, and season four is my least favorite season right now. Glory's cool in concept but lacked something for me in execution, and it would be a shame for her to be the last villain Buffy ever faced.
Season six right now is one of my favorite seasons (which was formerly the third season) and it has some fantastic episodes. The Trio is great for a faux Big Bad. I haven't seen season seven in its entirety but I *loved* what I did see. Caleb was awesome and the finale, "Chosen", is a much more fitting finale than "The Gift".
While "The Gift" was among the best Buffy episodes ever, and was very touching and all that, the show still felt incomplete. There was still too much to cover, too much characterization to go, too many more stories to tell...I think that "Chosen" had more feelings of closure than "The Gift" did.
And N4H, in a perfect world we'd be waiting to see next week's episode of "Faith, the Vampire Slayer", not season 3423948203948 of Buffy. 😉