Not exactly. In the case of Ankhseram here, it's not meant to put Zeref and Acnologia out of the picture. It's more like it has to appear just so it can be defeated. In many ways, all of Zeref's actions is really just him trying to give the deity one big middle finger, so it appearing before Zeref gives him the chance he's truly been looking for. To destroy Ankhseram.
Also, just thought of a possible plot twist: What if Lucy gets the Ankhseram curse? Think about it. She saved Natsu's life in the nick of time by rewriting his book. That to me, is likely a flagrant violation towards Ankhseram. Natsu should've been dead, but because Lucy interfered, he didn't. Thus, she is given the curse of Ankhseram.
Then its no excuse to why they got defeated so easily Zeref literally absorb Fairy Heart which had infinite magic power Only to be beaten by Natsu making a speech about friendship, While Aconologia who can absorb all magic gets killed by a deus ex machina by being pushed by a character that only appeared in this arc and a side character that not many cared about outside except some diehard Fairy Tail fans.
Do you mean the final fights of Naruto and bleach along with Fairy Tail. Nothing will top naruto's awfulness, so I welcome fairy tails ending til Natsu does the rivalry thing with Lucy and gets with Lisanna.
So Lucy becomes the new zeref and starts the whole thing over again, what's next erza becomes the new acnologia?
Oh I think it could be very well argued that Fairy Tail's Final boss battles are much worse than both Naruto and Bleach's depending how this play out, because at least Naruto and Bleach's didn't get taken out by the power of friendship (Zeref vs Natsu) or the main characters at least did the final blow instead of side characters likke against Acnologia.
You think you can never be any more disappointed, and *BAM*!!!!!!! 
Although I admit the August subplot was actually quite well done. But my point stands, I found that last bit of dialogue between them CRINGING rather than heartwarming. On a plus note While I don't particularly like how the Zeref and Acnologia fights are resolved or even handled at least I can say they did not unnecessarily drag on and at least they did not bull kitten like Naruto where the solution of defeating an overpowered villain is having an even more overpowered villain come in last second and kill the last one off 
if there are 10 chapters They better conclude the story properly. I'd say that I would like a confrontation with Anhkseram but that would actually fall in line the the "Kaguya" problem so I'd rather not
