Let me try to think of a way to answer this succinctly.
First, on the subject of maxing out characters or achieving very high ability scores to be considered "viable": "Viable" in DCC RPG means you survived a zero-level adventure and now get the chance to earn level 1. The game works on what I have come to call the "character funnel." First, everyone rolls three PCs per player. Their ability scores are 3d6 straight down the line, they're all 0-level with minimal equipment, and they have 1d4 hit points each. 1 or 2 (or sometimes all 3) of these PCs are killed in the first adventure, leaving each player with 1 or maybe 2 PCs at the end. Then, from this pathetic bunch of anti-heroes, classes are chosen based on what the survivors' ability scores and Luck rolls best suit them toward. I rarely see a character who rolls an 18 on anything -- and it is rarer still that such a PC survives level 0. (I actually played in a game two weeks ago where only one out of 21 0-level PCs rolled an 18 Strength. He was a hero! With +4 to hit he was always in the front lines stabbing away with his pitchfork. Unfortunately, heroes die fast in this game. He never made it to level 1. On the other hand, the pathetic farmers in the rear ranks did
survive...with their Str scores in the 8-11 range...)
This is the "character funnel" and it is how I ensure there is no min-maxing or power gaming. All chargen is randomized and every character has to "run the gauntlet" at 0-level simply to survive.
Second, regarding monster construction, 3E had this elaborate process for the correlations between monster HD, AC, ability scores, skill points, and so on. Remember how it would take forever
to build a monster in 3E? (Side note: I had to actually hire stat editors under 3E to specifically check all the math on the published stat blocks -- too many interconnected complexities!) This annoyed me not just for the time expenditure but because it has absolutely no impact on game play.
Little-publicized fact regarding my attitude toward stat blocks: yes, I hired stat editors to proof them because there is a segment of the gaming public that demands accurate stat blocks, but wow, does it really matter?? At all?? If you forget the synergy bonus on Climb in the orc warlord's stat block, will it EVER come up in game play? No!! Rules that do not affect game play should simply not exist. Rules that the players will never encounter should simply never be published. There was far too much complexity in 3E which simply had no impact on game play. I could run a game where the orc had the exact right stat block, and run another one where I slapped something together that was more-or-less right, and to the players
those two games felt the same. So why spend all that time on the monster stat blocks?? If a rule doesn't impact the players, don't waste the pages to print it. This is why we have 400-page rule books nowadays, when the game took 64 pages to explain in 1982...
Okay, rant mode off, but you see my point. In DCC RPG the monster creation system is much more free-form. As such there will be plenty of examples for monsters to use as examples, and the judge is encouraged to create many of his own monsters, too. There are plenty of examples in literature of creatures that have legitimately 20-plus armor classes (the iron statues faced by Conan in Iron Shadows of the Moon immediately come to mind) but there is no system mandating that "a 10 HD creature must have a +7 armor class bonus", so there will be no direct correlation between HD and AC unless the judge so wills it.
As for the "combat slog," again, opposite circumstance. Combat ends quickly. PCs still die way too fast. Working on it.
I guess the simplest way to answer is to say: I really like the core mechanic of 3E, which is to "roll d20, add something, and try to score high enough to beat a target value." That doesn't mean I like feats, skill points, attacks of opportunity, miniatures, combat grids, the monster stat system, prestige classes, or certain other things that add complexity...
Hope that helps. Bit of a rant but I hope it makes sense.