Once again, Jaron, realize that I interpeted your "tier 3" as meaning "lower the level of power for the overly powerful" as well as "increase it for those who are too weak".
And 20th level is not merely "action movie hero". Its "Hercules, move over."
And regarding magic bows...if his bow is enchanted to be "can shoot off a fly's testicles at three kilometers.", that's one thing. A "hits even harder and more often" is not going to compensate for the wood here.
And in regards to said other classes: Ew and ew and ew and ew and ew.
I'm not stating "the fighter is too strong!". Note the suggestion for "can hit with great accuracy" as a replacement...I'm not interested in the fighter being weak, at all. And being able to shoot at two hundred yards (4 range increments + Wisdom 18) with the same accuracy as at 50 feet is nothing to scoff at.
I'm stating that shooting over half a mile a power that is unbelievable...the fact that other classes can do even more unbelievable feats of archery should obviously be seen as coming in under the "This is also absurd", rather than reading "Fighters shouldn't be able to do this but (other class archer) can."
That is not the point, never has been and never will be. The point is that a yew bow simply cannot launch an arrow further than about 400 yards. A dragonbone bow, maybe. A bow of thiswoodthatissuperiortoanythingonEarth, maybe. Both would be special bows (if not exactly unobtainable for our wannabe William Tell/Robin Hood/Artemis.)
As for equipment, I'm saying that the problem is that while it can be somewhat justified for the character to do feats far beyond anything on Earth, that he should still have to have equally epic (small e) equipment to do so.
I don't mind action movies as long as I can believe that it would be possible...however unlikely...to pull off a given feat. I like my rpgs to do the same thing...running the mile in four minutes or less should be a feat (small f). Taking on ten men at once should be a feat (big F, probably).
For instance, I can imagine the Musketeers charging a group of guys with the firearms of the day without getting seriously hurt because I know (as a student of history) that the accuracy of those weapons was abysmal and that the training of soldiers in marksmanship was nonexistant.
So, draw a volley at fifty yards or so (outside the easy-to-get-hits range), then charge. The sheer shock of seeing something that audiacious, and the complications and timing of reloading a musket of the day will mean that you have a fair chance of pulling it off. (In our world, Murphey is a dick and will find a way to screw it up most likely, but Murphey is a daemon of our world, not of Dumas's.)
Action movie worthy? Oh yeah. (I believe the soldiers fired at closer range, but this example of Musketeer badassery is taken from the Man in the Iron Mask movie.) Heroic? Definately. Cool? Definately.
Believable, too, for the reasons stated. Its something that one can imagine that if things "worked right" could be pulled off, but doesn't require any powers beyond that humanity can concievably muster to do.
On the other hand, having Private Joseph Donovan be able to charge a position held by an equal sized number of Germans (to the number of guys the Musketeers above charged) who armed machine guns, one of the best armies of the world at the time, and come out equally unhurt...
That's not believable.
And I don't think D&D needs to represent the literally superhuman (and capable of doing great feats with boring ease) nearly as badly as the heroic-but-(larger-than-life, yes)-human (capable of doing not quite such great feats but being awesome in doing so.).
Orion: An alternate suggestion. Instead of trying to make Fighters (or Monks) able to do things equal to Miracle and Wish, why not make it so that Clerics and Wizards are on a power level closer to Fighters and Monks (as in the PHB)?
For all intents and purposes, even a 5th level spell is "the impossible" by anything we can replicate via technology as of now. I'm not saying we need to cut them back THAT far, but it is an observation.