drothgery said:
It's not a problem if you're the one playing the wizard. It's a problem if you're the one playing the fighter, because rare casters probably means rare magic items (unless it's really easy for the few spellcasters to make magic items), and that in turn means that the wizard is going to outshine the fighter, who can't keep up with the wizard without magic weapons and armor. And it's problem if you're the DM, because the wizard is the star, and the fighter is complaining that he thought this was going to be a low-magic game.
Actually, this is a "half-empty" view of things. See it from the side of how the GM would counter this...
In a standard campaign, the Fighter would gain a simple sword, than masterwork, +1, +1/holy, +2/holy, +3/holy, +3/holy/vorpal, etc. etc. etc., the weapon climbing in relation to the Fighter's level.
In the scenario you describe, what would likely happen (if there was a PC spellcaster) is that the Fighter would go from simple, to masterwork, than additional masterworks (per HoHF: Dwarves, Arms & Armor, Mercenaries, and other sources), and then around 10th Level reclaiming a mighty weapon of valor, a +5/Holy/Vorpal weapon and keeping it for the remainder of his career.
And that's just one example from an infinity of possibilities.
The problem you illustrate as being a feature of LM games with a spellcaster PC isn't a feature of LM games; It's bad game mastering.