I'm not much of a melee weapon user, but I do have to admit that going from "quick melee" to "your melee weapon's combo depending on what stance mod you have" has proven rather jarring, especially with the staff stances (the one I had equipped on my Amphis caused me to slide several meters forward at the end).
Charged attacks don't really feel any more powerful than regular melee attacks, though that's more to do with the amount of damage melee inflicts than anything else.
The automatic blocking is kind of cool (note that abilities like Iron Skin will prevent it from occurring)? I dunno how effective it's going to be as a defensive tactic, though.
The ability to aim melee slams is really nice, though hitting aerial enemies with a melee weapon (drones, namely) remains difficult. More often than not I've tried to hit them with a slam attack only to fall right past them.
They didn't even need to remove quick melee to implement this system, but they did anyways.
I suppose the alternative to "immediately enter the full melee mode" would be "quick melee attack, and then enter full melee mode"?
In any case, this is just the first phase of melee changes, so maybe wait to see the entirety of the changes before you analyze how and why they're totally fucked. For all I know, the devs might drop two or three of these changes before the month is out (though I dunno how likely that actually is).