Yes, I remember (dimly) AD&D casters also, and your point about them is well-taken. It just seems to me that 5e has gone too far in the other direction. But to be fair, I think my complaint rests on more than cantrips (and on more than their at-will-ness); they are a principal contributor, but not the whole story. The other major part of the problem is that you cannot turn around without bumping into a caster. And, of course, then the majority of them get cantrips. The overall effect is that spell casting becomes magical-in-name-only, as it is ordinary, commonplace, unremarkable - mundane in the common sense of the word.
So when the wizard casts
Firebolt, well, shrug - it doesn't feel any different that if he shoots a crossbow. He makes an attack roll and he can do it every round. What's the difference?
My other complaint about cantrips is the business of damage scaling with level in order, presumably, to ensure that our poor caster never feels left out. Eff that. That's the way casters (or at least wizards-as-successors-to-1e-magic-users) are
supposed to feel in return for the limited* occasions when they can grab the spotlight and do something awesome that no one else can even come close to. Oh, but I forgot;
everyone is a caster now, so they aren't that special anymore, so yeah, I guess we have to do that because we wouldn't want different classes to actually play differently or anything.
Not to mention that at-will spell casting opens the door for abominations such as
Guidance. 
Not to mention that by the way now many casters get a decent at-will ranged damage capability that bypasses both the need to have a weapon in hand and the need for ammunition. (Admittedly this is a complaint about particular cantrips, not cantrips in general. But again, if you have at-will spell casting at all, you probably get some version of these.)
</rant>
though I'm not sure where I should have put the corresponding <rant>
* And, yes, I still agree 1-2 times per day is maybe a little too limited, but that really only applies at very low levels. And in 5e it starts at 2 and goes up fairly quickly. Thinking about it, I'd probably be in favor of a slightly faster ramp in #s of spell slots if I could get rid of cantrips. Or have a fairly generous,
but not unlimited, supply of 0-level (cantrip) spell slots.