In my opinion having Buffy play a large role in the finale episode would have been a huge mistake, but I also think not including her at all was a mistake too. I loved LOVED that last episode (btw I just watched it today. I've been a huge Buffy fan since it came out but I stopped watching Angel after season 3, just got too wierd for me. I just recently rewatched season 1-3 and for the first time wateched seasons 4 and 5. 5 was easily the best season, but I digress and I'll talk more about that in another thread.) Yet despite how much I loved the episode I have to say my first reaction after it ended was "THAT'S IT??!!" And the cheesey "Thank You" at the end was lame, save that for dvds. Anyways, here's my perfect ending:
Angel says his final line "Let's go to work" and they pan out to show a women behind them in the dark. You can tell she has blonde hair but you can't see her face. She yells out "Hey boys, are we too late?" Behind her emerges her army of slayers. Cut to angel and spike smiling, and then the whole group charges into the battle.
Some variation of that could have been amazing. And you wouldn't even have needed SMG for it, all you'd need is 10 seconds of her voice and they can get that anywhere. I dunno, that way the battle would have seemed a little more fair, Buffy is kinda involved, and we have hope that they survived. Because let's face it, we all know they died. There was no way they were walking away from that army. And it's sad, I feel like just letting them all die is kind of disrespectful to the characters, especially Spike. I feel like if they were going to drag him back it should have been more meaningful, not just to kill him again a few months later.
Anyways I still loved the last episode, minus the last 5 seconds, it had comedy, tragedy, and a somewhat sense of closer (again, minus the last 5 seconds). I hope Joss gives us a hint in the Buffy comic as to what happened to these guys. Damn, that was a long post.