Frankly, this sort of response always amazes me (not calling
@UngeheuerLich out, but just as an example because this happens in many threads) . It is like when people claim "this is a solution looking for a problem." Maybe an OP isn't clear as to why they think something is an issue, but if they didn't feel it was an issue why would they bother posting about it? A lead off like "So why do you feel this is an issue for your group?" would be more engaging for discussion IMO.
Anyway, while I can't answer for the OP I can answer for our group: Yes.
Spamming cantrips makes combat feel like a laser-light show with
pew pew every where and martials dodging blasts hoping not to get caught in the crossfire. It is also extremely boring. Players complain sometimes about the limitations of martials of always just swinging a sword, well casters complain about always, "Well, I guess I Firebolt again or Toll the Dead again or whatever..."
YAWN
Part of this is the fault of the design in 5E. Too many spells require concentration so casters can't impact combat in ways they used to and instead feel their best option is to deal direct damage.
It also certainly makes magic
FEEL less magical in the game. We understand it for martials, its "what they do" when they Attack, but for casters I want their default to be "Cast a Spell" not always "make a spell attack". If you
want to fight in combat, be a martial class, that is what they are there for.
If a wizard can always have a light spell active?
Yes. It is bad enough that nearly half the races have darkvision (it is probably more now really), but with infinite
light darkness is never the scene-setter it can be. It removes mystery if you can always peer into the darkness and see what is there. I would rather it be a 1st level spell again (which BTW we changed it to) with a long duration, like 8 hours, so you
can do it but it has a resource cost.
If a wizard can fall back to attack cantrips?
Yes. Because they don't
fall back on cantrips when they run out of spell slots, the cantrips are the "go-to option" and used more often than spell slots ever are in combat, with the only exception sometimes being healing spells depending on how the fight is going.
So, while this might not be an issue for most tables, for some it is. I'm not the only one whose posted house-rules to nerf cantrip use.