Why would somebody play an non-caster?

[Shining Wrath]

Because you're playing a CHARACTER, not a collection of powers.

Because Conan, Aragorn, Boromir, Athos, Porthos, Aramis, D'artagnan, and Fafhrd, among others, are some of the most interesting people in fantasy literature.

Because the protagonist of just about every FRP video game you've ever seen is like Cloud McStrife, not like Aerith Gainsborough.

It's fun to be the badass who can take on a giant with nothing but his own brawn and a length of steel.

If your sole point is playing D&D is to always, every encounter, be the one who displays the most power, don't come play with me. I'll mock you with no mercy.

This. The Tier system should be descriptive, not predictive. The Tier system should make people aware of the abilities and limitations of a class, relative to other classes. In a vacuum, it should not be used to tell people what they should and should not play.

That's what these forums are for.

Now, a DM might tell his players that he only wants Tier 2-4 classes, for the sake of balance and control in the campaign. Or a player may wish to only play Tiers 1-2, for the feeling of power attendant to such classes. ... SNIP ...

"Dogmatically follow[ing] the tier system" is like dogmatically following the dictionary - the book simply tells you what the words mean, not which words are better.

My next campaign our DM hath decreed that we can single-class Tier I or Tier II, or gestalt Tiers III, IV, or V, with an exclusion of no double Tier III. I'm leaning toward a Sorcerer with Stormborn PRC if I can big-deal him into allowing me a bloodline for free (because otherwise Sorcerers tend to be like other Sorcerers), or a Cleric with Malconvoker PRC, one level dip into UA Conjurer because fast summons are Teh Awesome Sauce.