I partially agree with the benefits of this. I mean if they wanted to re-imagine Doc ock for example( a wonderfully cinematic villain) they could simply recast him and we'd be left with a mixture of newness and familiarity(ignoring that the character has already been killed in that universe).
The problem comes with the damage to the story Raimi verse already did. Especially with the SM3 retcons. I don't even know what to believe when it comes to uncle bens death. And venom...
When going with recasting it's a lot more natural a process to start from the beginning. The last 5 well received reboots of the decade, weather fans want to admit it or not, have rebooted to the origins. Batman, StarTrek, Planet Of the Apes, Casino Royale, Xmen. While it's true that they mostly treaded new ground and gave the audience mostly unseen stories. One can't be completely blind to the logistics here. It's just more organic a sell to have a new younger cast(younger, always younger), starting from the beginning. It's going to happen with superman, hell, it's happening with Lord of the Rings too.(I'm excluding prometheus)
ASM made some funky choices here and there, but they also made some great ones. I'm personally waiting for the sequel to see if any of this really paid off. Financially, they've already won the argument.