Plus, both of these make cantrips even more like weapons, which is a distinct disadvantage in the "keeping magic magical" direction.
I think this is the biggest issue for me.
One of the complaints about 4E was the fact that there appeared little differentiation in game mechanics between weapon combat and magic combat. Regardless of the method you used, they all attacked the same way, they all were defended the same way, they all did damage the same way, they all pushed/pulled people the same way, they all moved people the same way, they all healed people the same way. The only difference was the narration we were meant to imagine and attribute to what was happening. Very few times could you look at the purely mechanical aspect of any power power and glean from it "That's a weapon attack" or "That's a magic attack".
'1d8 damage and push the target 1 square' could mean anything.
With other editions of D&D (including 5E), they seemed to be a purposeful mechanical differentiation between attacks using weapons and attack using magic. Now granted, they aren't
widely disparate from each other by any stretch... but they do run differently. And that does help lend itself I think to making it
easier to distinguish one from the other and that separation allows for an easier visualization for their differences. When 5E weapon attacks have multiple attacks with multiple attack rolls plus add in a single higher bonus to damage based upon ability modifiers versus magic cantrips that are often defended via saving throws and whose damage has no flat bonuses and instead do additional dice of damage (depending the level of the caster)... that difference in game mechanics aids in the differentiation of narrative as well (however slightly it may help).
Now obviously that differentiation won't affect everybody-- people all visualize mechanics and fluff in different ways and thus this subtle different between 4E and 5E at-will combat with weapons/spells might have absolutely no impact on how they suspend their disbelief-- but I would suggest that having two different mechanical systems to represent two different narratives is probably easier for
most people to grok than using a single mechanical system to represent two different narratives. Not for
everyone, but only most. And thus in my mind merging both weapons and magical implements back into a single mechanical system would not necessarily help for a lot of other people.
But if it helps your
specific table? Then go for it! It matters not what the rest of us think.