/snip
EDIT: If two classes in 4e had access to the same power I wouldn't call that samey because it's one power with various classes accessing it. Versus two distinct powers that are supposed to be different but play out, appear, feel, whatever very similar.
This, right here, is probably the core of the disagreement. Imaro says that multiple classes having the same power doesn't make the game samey. So, presumably, the fact that every 5e class heals the same (cure wounds spell) or attacks the same doesn't make the game samey. These things ARE the same, so, they get removed from the equation.
To me, this just speaks to perception. The difference between 4e and 5e, is that 4e would actually try to differentiate these effects, somewhat and to varying degrees. So, sure, you get a Howl Warlock power as a 9th level encounter that looks a lot like a 1st level wizard at will Thunderwave. And, again, with thousands of powers spread over 40 classes, there's going to be overlap. That's unavoidable.
So, presumably, had 4e simply had a pool of powers shared across classes with a handful of class specific powers, then
@Imaro would no longer find it samey.
Which, to me, rolls it right back around to presentation. You could argue, I think, that 5e is more efficient in its presentation because it doesn't reprint similar or same powers across different classes. You don't have a different Cure Wounds spell for each class. You have one Cure Wounds spell that works the same for all classes. You don't have a grab+attack power for a bunch of different classes, you have one grab+attack power that works identically for all classes that have extra attack.