I mean, if you are ok with a wizard having mass flight spells to overcome pits, what's the problem thinking that a 'super hero' can't jump distances that are greater than normal mortals could hope to leap?This line of reasoning is perhaps one of the central divides between "new school" and "old school" play, or at the very least, between those looking for a high-tactics, high-strategy man-to-man scale wargame and those looking for a game focused more on problem-solving. You see it in accusations of wizards "stealing the spotlight" from fighters with a Fireball spell, or from thieves with the Knock spell. You see it in bragging about how, in newer editions, everyone gets to be awesome, instead of just the wizard.
But, as I just alluded to, not everyone is looking for a style of play where "everyone gets to be awesome" and "everyone gets their moment in the spotlight". It certainly doesn't seem to be evident in the original rules, which is why rules variants and eventually whole re-designs popped up to support the new school style.
What some people don't get is that the Fighter and the Magic-User, in old school design, are basically different options for how to play the game. The Fighter player doesn't have a lot of special tactics and options to learn. You buy equipment, you hire help, you decide whether to fight or flee or negotiate, and you get richer (or die.) It's a simple character to play. The only decisions that need to be made are those relating to the environment. No special knowledge of the rules is necessary. If you decide you want more options, you can either find (or commission) a magic item, or change classes (if your stats are good,) or start over as a Magic-User.
The Magic-User, in contrast, has an extra resource-management mini-game to deal with. Spells are basically extra equipment: one-shot powers. The Magic-User starts with a basic list and must choose exactly one spell for the coming adventure. Playing a Magic-User requires more strategic thinking. The M-U's options expand as the levels increase, but note that an M-U can't just cast Fly an infinite number of times, as needed, but must actually pay money to research Fly, then prepare Fly (instead of Fireball or Clairvoyance or Haste,) then cast it when the time seems right; once cast, the spell is lost, so the player of an M-U must hope that there is no better spell to prepare than Fly, and no better time to cast it than at that particular moment.
In other words, Fighters are a simpler option than Magic-Users; making them work the same limits everyone to one play style, and is thus not as enjoyable for those who are looking for a simpler option.
There's another objection to the Fighter with all abilities scaled to level, which I may deal with in a later post.