Majoru Oakheart
Adventurer
After playing D&D for over 25 years with hundreds of people I have yet to meet anyone that felt they were not having fun because they were "only" a fighter.
I've met people who were annoyed that they were only a fighter. Our experiences differ. I've met a number of them. Often, the people in question didn't speak up to let their opinions be known. But we used to discuss the game in between sessions a lot. We had no lives to speak of.
So, often the talk was about "I feel like I'm not useful to the party. I'm just there to be the meat shield and hold off the enemy until the Wizard fireballs them all and kills them. Then, I'm supposed to roleplay my low intelligence so that the Wizard who is roleplaying his high intelligence can figure out the answer to all the riddles and puzzles. Then I have to roleplay my low charisma and be dumb and not very friendly...so I avoid talking to people in social situations. Meanwhile, the Bard or the Cleric does all the talking. What do I do that is useful and recognized better than everyone else other than have more hitpoints?"
The answer given was normally, "Well, we need a fighter. Otherwise the rest of us would die. So, you can't switch characters."
If a DM has proper system mastery, the well prepared caster is never a problem.
As for "proper system mastery"....I have no idea what that is anymore. One person's complete mastery is another's "Not yet ready to DM."
One of the examples I always use to demonstrate this was a time where the DM decided to create an ongoing villain for the group in a combination 1e/2e game we had. It was a female Wizard. We were supposed to meet this Wizard when she used Projected Image to create an image of herself while hiding in a well hidden secret chamber nearby. The Wizard was supposed to threaten us, attack us with spells through the image and then teleport out if we lived.
What ACTUALLY happened was that the player who was playing OUR Wizard immediately guessed that it was a Projected Image. The rest of the party ran up to her in order to attack. He hung back. The enemy created an illusion of falling rocks on us and most of us were pinned, believing the illusion. He, on the other hand, looked for secret passages.
The DM got a really worried look on her face and said "Why?". He said "Because the range on Projected Image is short. She has to be around here somewhere. Like in a secret room connected to this one."
She told him that he couldn't see any secret doors because this one was really hard to detect. He cast some spells to detect secret door, I can't remember which one. There was a brief argument over whether the spell could detect it. The description of the spell was consulted. He found the secret room, opened it and surprised the enemy who had no idea she would be found. She then pointed a Rod of Disintegration at our Wizard, figuring she could finish him off and teach the player a lesson for being a little TOO crafty. The Wizard said "I use my ring of telekinesis to grab the rod out of her hand." The DM insisted he couldn't do that...the description of the ring was looked up...It was decided that it DID work that way...The player won initiative and then used the ring to grab the rod. Then the DM said, "Fine, you get a rod. But she's high enough level to just teleport away and nothing you can do will kill her in one round." The player considered this and said "You're right. Does the wand at least have the command word written on it?" She said yes. Then he used the rod to disintegrate the enemy. He won initiative because the time to activate a Rod is much faster than casting a 5th level spell.
Then the DM complained that we needed to end the game there because she didn't have anything else planned out. Her entire adventure hinged on that Wizard surviving. And to add insult to injury, the player asked where the Wizard's spellbook was and the DM said "Not here, she left it elsewhere" and the player went on a tirade about how "No Wizard leaves their spellbook out of reach, besides, we had evidence that she'd been here for multiple days and she had been casting spells during that time. She needed her spellbook to rememorize the spells." Until the DM was forced to agree, that yes...the spellbook was in the room. Which he then promptly picked up and due to the XP for GP rule from 1e gained 4 levels just by picking it up(he convinced the DM that each spell in the book should be assigned the GP value of a scroll of that spell, since they essentially WERE scrolls).
And that was a problem that a simple Ring of Telekinesis and a spell to detect secret doors caused. One could say that the DM didn't have proper system mastery in that she didn't expect someone to figure out that the Wizard was hidden nearby, have a spell to detect secret doors, followed by the ability to disarm a powerful magic item and make plans accordingly. But she had no real reason to think that those combination of things would happen. Plus, she had enough system mastery to think of using a Projected Image instead of putting the enemy in the same room with us.