You know, it's really nifty to have things like Power of Skill in the game, letting you use At-Wills as basic attacks. But it's fundamentally a bad idea.
So many other items, feats, feature, etc, are all based on the idea of affecting either Melee basic attacks specifically, or affecting only powers of a certain category. With the latest Hybrid rules for Executioners, we get to see this again-a hybrid build that's supposed to apply only to melee basic attacks but, combined with powers from another class (such as Warlock), makes for a hybrid striker that basically has the striker features of two different classes.
And it's not just hybrids. A Knight Half-elf with Eldritch Strike and a staggering weapon can essentially automatically hurl opponents away, negating enemy attacks against allies entirely.
When something calls upon a melee basic attack, it's making the assumption of what a melee basic attack does-namely, damage, and precious little else. When you have ways of applying everything from slide to daze to melee basic attacks by having melee basic attacks not be melee basic attacks, that dynamic fundamentally breaks down. It's an awesome game mechanic, but it's a Pandora's Box of imbalance.