Vyvyan Basterd
Adventurer
The thing I find hillarious about this is that you just made a striker... not a defender.
Not too surprising since previous editions provided no mechanical class ability to defend. All you really had was tactical positioning. Someone mentioned upthread that there was something similar to OA in 1E, but I don't even remember playing with that rule. So basically they redefined the fighter into multiple classes. I don't really understand peoples' hangup on the naming convention, but obviously it is an issue for some.
As far as 3e goes -
elf fighter 20 dex 14 str rapid shot, point blank shot, weapon specialization, compond bow - weapon finessed rapier for backup.
And what armor was best for this elven fighter? Light or Heavy?
So, what you again seem to be saying is that in your experience Rich Baker's premise is correct that the last decade of design is less supportive of role-switching.
With the example of the potion-administering fighter? No. I think the post-AD&D supports that more by suggesting characters be able to purchase magical items more freely.
Outside of that specicfic example: Recently in my own game the defender stepped out of his role to use the Heal skill on the fallen leader to revive him instead of just swinging his sword. Many fighters can be built for effective battlefield control. And many fighters, before the advent of the Slayer, fulfilled the role of striker through weapon and feat choices. Most of the classes had secondary roles that they were competent in from the start of the edition.
Let me ask, are you assuming there are a certain number of players? Are you assuming that certain character classes will need to be represented and in certain numbers for a given group? Your use of the word "tailored" above seems to suggest your premise(s) includes design mindset ideals of the last decade or so. These are assumptions also made in design over about the last decade or so. It's not uncommon prior to the last decade or so for groups to be larger, sometimes much larger, than 3-5 players and for campaigns. While one player might wish to optimize for melee combat if they had an 18 to put into one of their ability scores, there might be several (or more) fighters in a group and given that many campaigns spent as much time out of dungeons as in, or even rarely went into dungeons, ranged and mounted combat were of greater importance. But you sweep all of that aside as if they are not even a consideration for your thought experiment and that, again, seems to support Rich Baker's premise regarding how "roles" have become codified in the last decade or so.
In my group its was always deemed that someone "had" to play a thief and another a cleric, as those were the only two classes that could, respectively, find/disarm/unlock and heal. Currently one character might spot the traps, another disarms/unlocks (not always a rogue, last time it was the warlock), and any leader can heal without "forcing" the player into cleric. Our campaigns seem to spend as much time in and out o dungeons as they always have. My experience has definitely been in the camp of the roles always having existed in one form or another.
Is this codifying in a particular role? Or is it just dangling a very nice carrot in front of you that you can't pass it up? How does that track with a cleric who gets ahold of gauntlets of ogre power?
This is definitely a change from prior editions. If you've chosen to build a cleric that relies on ranged attacks, finding a powerful melee weapon will not appeal to the character and would most likely end up in the hands of another character, magic items are certainly more tailored to specific users (which I'm not the biggest fan of either). But again, this seems to be an example of roles changing based on items found, similar to Mark's example of the potion-administering fighter. It's not really based on the choice of the player but instead the whim of the DM or luck of random treasure tables.