D&D 5E Things that the non-magical Fighter could do

[Nagol]

Going solely on level, sure, but it's also worth noting the additional restrictions on MCers. For example, with F/M:

1) No School specialization (this was a big deal in 2E).
2) Armour restrictions (depending on race, DM, and other factors, but certainly much more restrictive than a single-class Fighter).
3) No Weapon Specialization (by default, again, some DMs allowed this, as did some kits).

Pretty sure there was other stuff too.

Multi-classed also lost hit points (you round down).

I agree the multi-classed characters were reasonably comparable to single-classes though I think they operated at closer to 90% in each class than 70% -- for the levels where they were able to advance, anyway.

I never found school specialisation worth it when I played a Magic-User; you surrendered too much so that's probably a play style thing. Armour restrictions worsened you compared to a Fighter, but not compared to the Magic-User. Weapon Specialisation loss can be a big deal if the optional rule allowing it is in use in the first place. Typically, it is used.

Compared to a straight Fighter, a F/MU

• needs an Int score
• Loses hit points
• Gains improved saving throws vs. Rods and Spells
• Loses weapon specialisation (if the optional rule is in use)
• Gains extra non-weapon proficiencies (if the optional rules are in use)
• Uses the to-hit chart one level lower (typically -- it varies of the course of the career)
• is very restricted in armour (elven chain or magical defences only e.g. bracers, ring, and cloak)
• can cast spells as if he were a M-U one level lower than the straight Fighter (typically -- it varies of the course of the career)
• Can use items restricted to M-U
• Has a cap on level advancement

Compared to a straight Wizard, a F/MU

• needs a Str score and can take advantage of a high Con
• Gains hit points (especially if Con is 17+)
• Gains improved saving throws in most categories
• Gains more weapon proficiencies
• Much better at attacking (6th level Wizard is the equivalent of 2nd level Fighter, 9th is 3rd)
• Can wear some armour (elven chain)
• Can use items restricted to Fighters
• Must be a Mage rather than a specialist
• Casts spells as if he were a level lower than a straight M-U (typically -- it varies of the course of the career)
• Has a cap on level advancement

 

[Neonchameleon]

Going solely on level, sure, but it's also worth noting the additional restrictions on MCers. For example, with F/M:

1) No School specialization (this was a big deal in 2E).
2) Armour restrictions (depending on race, DM, and other factors, but certainly much more restrictive than a single-class Fighter).
3) No Weapon Specialization (by default, again, some DMs allowed this, as did some kits).

Pretty sure there was other stuff too.

First edition was specified; school specialisation and weapon specialisation weren't relevant.