Eh, even an intentionally non-optimized spellcaster can have fairly complex options to consider even early on, if the environment itself is complex -- outdoor engagement involving multiple combatants, perhaps non-combatants to protect, buildings or other terrain variously blocking line of sight, providing hard cover, maybe firing positions.
I once ran an intentionally non-optimized GOOlock (2014 rules; this was well before 2024) that early on got access to Spider Climb, which meant that for a combat involving defending a village from a raiding party it was actually relevant to know things like the heights of nearby buildings and the shape of their roofs (to the extent of answering the question of whether it'd be feasible to use one for a firing position from which to be casting EBs).
Later on... shrug at one point I calculated that I had a first-round threat range of ~300' (walk 30', summon a beholderkin aberration 90' away, beholderkin could fly 30' more, +150' range eyebeam). The combination of being able to move a bit, summon, and both use the remainder of my movement and have the summon itself reposition to in turn make ranged attacks provided options in spaces that were large enough... and since at that point we were in a campaign featuring giant-sized spaces, that happened a fair bit. That EB could reposition enemies but only in a direction directly away from me gave me more reason to consider positioning, as well. More generally, for a campaign where you at times need to maintain a high tempo (e.g. no long-resting after each battle, but sometimes you want to clear a stronghold without ever stopping for as much as a short rest due to defenders being organized) casters in general have a fair bit to think about regarding resource management in addition to the obvious "one concentration spell at a time" limit.
You could avoid the resource-management dilemma of Vancian spell slots by using something like Shadowdark's spellcasting mechanics where you might randomly lose access to the spell you tried to cast (until the next rest, not forever!); or simplify it using a spell point/mana system, or even something like drain from whatever edition of Shadowrun is your fave if you're feeling like seriously overhauling things (not sure how that'd work, but shrug; I'm sure that people have homebrewed weirder mixes). Things like positioning... well, any system with multiple AoE shapes and rules regarding movement speed, ranges, cover, and lines of effect wants you to care at least a little bit about it, even if I'm sure that a decent fraction of people are probably content to run TOTM combat and not fuss too much about the details.
