For one thing, personally i dont see ben reilly in the iron spidey suit. He's not a hand me downs kinda person, he has his own look and personality. He could have easily kept wearing the spidey costume when he was scarlet spider or even worn it when parker was out of the picture for a while,
in both cases he didn't and re-invented himself twice. to now say that he would take an old costume of parker's is not like him at all. Money wise and all, reilly has had it worse than pete and has managed to get some things together so it's not even a financial issue.
I see nothing wrong with having ben and parker around still. When they were written and even now, they represent two different things.
Parker is more grounded now, less carefree and has repsonsiblities, it would have been better if he also had responsibilities as a father but so be it.
Ben's responsibilities are far less and he's younger at heart and more care free, his fears and enemies are different because he has different levels of exposure to them since overall he would have been away for around ten years.
plus his relationship to aunt may now that she's back would also be different and seeing whether she would accept him now is something that could be built on.
plus with all the power changes that have happened to spidey, one can assume that clones wouldn't be affected in the same way (kinda like how buffy is THE ONE while faith and the others are just slayers). Seeing how Parker being suped up affects Ben reilly being relatively ordinary and if that big brother relationship comes into affect and if ben has problems being not only a clone, but an outdated one, imagine all the webshooter vs organic jokes they could exploit.
plus any return of ben means the return of Kaine and that can't be a bad thing.
plus the greatest bonus of all, is that they can each help cover the other's secret identity by being around when the other isn't supposed to be there (parker with the altering suit can pull it off easier while ben has to do costume changes, again can add interest).
I mean what's better tha Norman having his own private spider-man to beat up over the last 6 years.
to be fair, of all clones and alternate timelines in all fiction, ben and kaine are the best. there aren't many i feel that are better than the original but in this case, i can say yep, they actually are.
plus ben's got better fashion sense