if you have a gmail id you already have cloud storage. Google Drive,Google photos,gmail,books,music,magazine etc.
icloud is just email,documents,calender and less than 5Gb of storage
iCloud is not like Google Drive, where most use comes from the user putting stuff there as if it was a hard drive. iCloud is designed to be a service-enabler (PIM, Photo Stream, App Store, iTunes, etc. all are backed by iCloud now) and repository for applications (i.e. WhatsApp just implemented the ability to back up your messages to iCloud). It works in the background - similar to SkyDrive on Windows Phone/Windows 8 except SkyDrive also allows you to directly place and manipulate files there yourself (best of both worlds).
Also, a lot of the stuff that is stored from stock iOS apps to iCloud doesn't count against your quota, so 5GB actually can go a long way to a non-power user, BTW.
iCloud works well on iOS because Apple's developers tend to follow their lead. It will be quite a while before you can buy an Android phone which integrates the services this way, or even find a decent set of high quality android apps that all use the same cloud storage service similarly to the WP8/iOS stock apps.
If that's the kind of integration the OP is looking for, he won't find it cause it doesn't exist on this platform - yet. There are some use cases that "Share" simply doesn't address (some = many in this case).
Google IS moving in this direction, albeit slowly - as I stated. You can already see it happening with Drive/G+ integration, Migration to Google+ Photos and Hangouts using Google+ Photos as a back-end for photo sharing. The strategy is different, but they are trying to achieve similar results. It will always be a poorer user experience, IMO, until they actually bake the services into the core OS like the others do, but that can be a problem given how Android is developed (plus they want to keep some APIs super secret/exclusive for the foreseeable future).