If I zoom out from that a little, to look at the idea of a "fire ray" as a game mechanic, this is what I see: you want a spell to be a tool, not an effect. This is something that 4e abandoned (attacks damage creatures and doors are not creatures!), but something every other edition has had. 3e said "Your fire deals X damage against a target. Shoot it at a wall, it deals X damage to the wall."
I'd actually agree that tools are more fun than effects in a tabletop RPG. Tools, by their nature, are useful for more than one thing. They encourage creativity. If my ability is "I shoot fire rays," then I will use that ability to overcome whatever problem my party faces, from the charging ogre to the locked door to detecting the sneaking assassin to winning over the noble who controls the roads in town.
That's a good way of articulating it. For both versimilitude and creativity, I do like spells as a tool. To extend this a little further, I'd like to see D&D, for example:
a) define the effects of cold magic, for example, so you know that cold does x damage and numbs (=slow) living creatures, or if applied directly to the ground, causes slippery terrain, etc.
b) keeps cold effects more or less consistent, so that any cold spell shares the same traits (as applicable). You've defined that family of magic and how it interacts with the world, and the various cold-spells are variations of shape, power, etc.
The thing is, this can create an imbalance.
In all fairness, did D&D ever really truly tried, and I mean honestly tried, to implement a balancing mechanism that does not take away the fun and flexibility of the spell-as-a-tool approach? Or did 4E swing sharply towards the spell-as-an-effect and other 4E paradigms because it was easier, convenient, etc.? I'm just asking, if anyone actually tried? People often accuse WoTC of not making the best adventure modules, but that doesn't mean that amazing adventures haven't and can't be developed. So just because D&D went with the 4E approach, it doesn't mean that the alternatives cannot exist. Maybe it doesn't, maybe it's impossible to have fun magic and no balance, but I'm not sure I want to rely on WoTC to give me a final answer. Maybe a 5E or another system will come around that proves it wrong.
If a wizard can both kill an ogre and open the trapped door, what does the thief do? If the wizard can also detect an assassin, what's the fighter do? If the wizard can also win over the noble, what's the cleric do?
I could argue that if a fighter can slaughter his enemies and smash locks, then what does the thief do? If a charismatic rogue can sweet-talk the noble, what's the cleric to do? But somehow that's not a problem.
Since all this is theoretical, at least on my end, I don't have any hard answers, and it would take an essay to cover every possible corner case, so I won't even try.
I do think it's a sacred cow that somebody decided in 1e/2e that fireball, for example, should do massive amounts of damage. What if magical fire is more like a flamethrower. If you're roleplaying a modern rpg, nobody claims that the guy with the flamethrower is hogging the spotlight with his worldshaking weapon. Ya, the flamethrower is unique and intimidating, but you can sneak from behind and knife him, or shoot him from a farther distance, or rush at him while he's firing up his flamethrower.
I'm not invalidating anyone's concerns about balance. I'm just wondering if people are too quick and hasty to give up on cool spells and sacrifice that potential fun because they never really thought it through.