Take your blinkers off. Why use the 'Spider-Girl' name for an unrelated character that is not Tom DeFalco's baby? Why not use a different name for a different character? It can't be to cash in on the name, since sales are so dismal for Spider-Girl. Rather the intent is to marginalize the original MC2 Spider-Girl, so when people hear the name they don't think of DeFalco's creation that he took so much pride in, but instead this new SG who has nothing in common with the original. As I already mentioned it didn't work when they completely changed Thunderbolts into something that no longer resembled what the book used to be. It won't work this time. I give this series 6-12 issues. Fans of the original SG will percieve it as a slap in the face and it will never build a base. This could have easily been avoided if they used an original name.
And you really think that most of the comic fans who read Spider-Girl for years upon years are so ignorant and stupid to not be able to know the difference?
I own like 120 to 130 issues of Spider-Girl. Trust me there is going to be a big difference between Mayday and Arana.
Nobody is telling you to buy the Arana series. I'm not going to buy it either because, honestly, I'm not interested and have never been interested in Arana. It's only a slap in the face if you let it be a slap in the face. The MC2 Universe dies if you LET IT die. Apparently there weren't enough readers or letters to save the book from another cancellation. Spider-Girl ran a VERY long course and told a lot of really fun stories. It's the longest running female character series Marvel has ever had.
I will agree that Arana's book will probably only last a a year, maybe two, and then be cancelled. And who is to say that Mayday won't come back in some capacity down the line again? Maybe someone else besides Tom Defalco will pick it up in the future. No character is dead unless the fans let them stay dead.
Take this thread for instance. Fans of Ben Reilly. The guy died in Peter Parker Spider-Man # 75 and, honestly, when I read that I thought I was never going to see or hear this character referenced in a Spider-Man comic ever again. Guess what? Kind of got proven wrong on that one because there are writers and creators coming up that were long time fans of the character themselves.
I'm a huge fan of Mayday and the MC2 universe. I would LOVE to see the character continue on forever but if the sales are not there, well, what can you do? And, no offense, it's not like Mayday has a copyright on the Spider-Girl name. Marvel does.

Seriously, you are taking it a little too hard and I know you're not the only one. Dead is never dead...unless you let it be...so don't let it be.