Ignoring these ridiculous and clearly fake "Vulturess" rumors for a moment...
As much as I love the Lizard, I'd be absolutely thrilled if we actually got the Vulture in this movie. I've always thought he was one of the all-time most underrated Spider-Man villains.
At first glance he might not seem unique or visually interesting enough but think about it; remember the aerial battle at the beginning of Spider-Man 3? With Vulture, we can take that to a whole new level. As far as the character himself goes, Vulture would be best done in a style similar to Norman Osborn in the first movie, portrayed as as a vicious character who, though he's placed in a sympathetic predicament--a human one, really--is also irredeemable, far too old and bitter to change his ways now. I'd like to see them use something along the lines of JM Dematties' cancer storyline, where Toomes finds out he has terminal cancer and instead of living his last days in peace, he instead seeks violent revenge on everyone who ever wronged him before it's too late.
Luckily, it does seem that Raimi recognizes the bitterness inherent to the character, judging from the dark way he wanted to portray him in SM3.
As far as him being old, well hell, that's the point! A vulture is a wrinkly, bald, old-looking bird, so Adrian Toomes is a wrinkly, bald old man.