I agree. I think both should be completely redesigned from the ground up, but they’re not interested in doing that in 6E.

• Wizards should be boosted in early levels and nerfed in later ones, and should be split into multiple classes focused around illusion, commanding undead, AoE damage, control, buff/debuff, etc. (but not all of them simultaneously).
• Fighters should get maneuvers and cleave damage focusing on one or few targets.
• Rogues can continue occupying their niche of single target, high risk / high reward critical damage (but note key phase: high risk). Etc.

Everyone should have a clear specialization with a little overlap. A class should be the best at a thing and adequate at something else.

Yes, OK, two sessions, maybe three since wizards level slower. In AD&D your GM should be awarding for good ideas, role play, encouragement of other players, etc. though, as well as enemies slain. And it’s common to be a little generous with XP in those first sessions.

There was a reason wizards carried daggers and slings as well in early levels.

I just get tired of magic users complaining that they need to do equal damage to fighters from the beginning at range and also be able to warp reality in higher levels.

Exactly, the single session where wizards are level 1 in an inaugural battle that likely lasts 2-3 rounds