I don't think I pretended anything. I took you to be saying that a dual classpemerton: I see how I erred in writing "at any time other than first taking the class". For rhetorical purposes, it was of course easy for you to pretend that I somehow considered the stated requirements for taking a second class as something else.
Fighter-MU can have less than 15 strength as a result of having reached 41 years or more, and hence suffering an aging penalty on strength. If that's not what you meant, then I obviously misunderstood you, but looking back over your post that still seems to me to be what it says.
No one on this thread said that it should be. I don't even think anyone on this thread criticised AD&D 1st ed.Neither have I -- or any other players of my acquaintance, and by evidence not the designer himself -- ever harbored the view that AD&D ought to be all things to all people.
To reiterate - I was simply pointing out that, like some other games (incuding 4e), AD&D has some features of its character build rules which constrain the sorts of fantasy stories that can be told using the system. For example, I think we've established that, within the rules as written, there cannot be PCs who are able to wield swords in combat, wear armour while casting spells, have learned their spells from scholarship rather than religious devotion, have a strength less than 15 (or, in fictional terms, not be strong enough to lift 150 pounds over their heads), have IQ less than 150, and be younger than 41.
Nor, by the rules as written, can there be PCs who are gnomish initiates of the druidic circles. Nor, by the rules as written (and excluding UA), can there be elvish PCs who are warriors of such renown that they attract man-at-arms to come and serve them (elvish fighter level cap being 7).
I can conceive, however, of such a wizard - maybe an Elric variant. I can conceive of such a gnome. And I can certainly conceive of such an elf - a type of Elrond or Thingol variant, for example, if not Feanor himself.
These are not criticisms of AD&D. They are just observations about it. Just like 4e, it is not a game that will impose no constraints on the sorts of stories it permits its players to tell.