I don't really like these "sustain" changes. I'm afraid if they stop AD carry + support from being the unstoppable force that it is, roaming will make a comeback.
Roaming sucked. You had to ward you own jungle in addition to the lanes, putting you even farther behind on money. If you were ever half-way out into your lane, you were over-extended, because if you were ever out of flash range of your turret, you were over-extended. As long as I've been playing, the game was never more passive then when roaming was popular.
AD carry plus support stopped that, because if one of the champions left bottom lane to roam, you wouldn't be able to stop the AD carry/support, and you would lose the tower.
--
"What if you just eat vegetarians?"-neonreaper
"^ You are what you eat. ^_~"-Koiji