I reject the idea that creating a rule for spells to fail and possibly backfire is the "easy" solution for casters having o'erweening power. And I almost resent the idea that because I don't agree with that solution, I'm somehow in the wrong.I really don't get why the so called "alternative" is Infinite Arrows with a pointless for show "downside". I get that it takes no effort to keep track of arrows when you will just roll some dice to see if you have infinite arrows. And guess you can reduce the damage, but does it matter with infinite arrows?
And I'm a bit unclear, does the character have infinite quivers?
I guess you will go through some bunch of abstract rules until you somehow decide the character has run out of arrows and can't access the infinite arrows anymore, for no reason.
Or, well, you could just count he arrows. It's much simpler.
This has always been hilariously true.
The vast majority of Gamers-"Spellcasters in D&D are too powerful and broken!"
The Lone DM- "Um, you know there are Official rules, right here in the books to address and take care of that?"
All the Other Gamers- "Oh, we don't use any of those rules."
But in the spirit of discussion, I'll give you my "easy" solution to the problem in 5e. Step 1: Remove Ritual casting; no casting spells for free just because they take awhile to cast. You want a powerful utility spell, you use a spell slot as Gygax intended.
Step 2: replace concentration with "you can only have one spell with a duration active at a time".