Forgive me if somewhere there is a better written and articulated article explaining this, but this is my re purposed ramble to my gaming group about the ridiculous vertical inflation inherit in Type 4 D&D.
Everything with a stat block in 4ed gets half its level added as a bonus (on top of special abilities, magic items and ability score bonuses) to its defenses, and to its rolls to hit and initiative and to skill checks.
Thus to break this down.
Lets say a level 1 peasant has say AC 12, Fort 12, Reflex 11, Will 11
This is from +1 of AC for padded clothes, +1 for Dex.
They have no bonus from level. They roll at +3 to hit (+1 for strength +2 for a poor quality spear).
They have 22 HP (Con +8).
A tiger (level 6).
AC 20 (+4 dex, +3 level, +3 natural) Fort 19 (+4 strength, +3 level bonus, +2 natural), Reflex 19 (+4 dex, +3 level, +3 natural), Will 17 (+2 wisdom, +3 level, +2 natural)
+11 for its bite attack. (+4 strength, +3 level, +4 for proficiency value of its teeth and natural).
+7 initiative (from memory) (+4 dex +3 level)
Now this may seem fine for your tiger and other beasties (which i don't necessarily disagree with) to have these stats but consider your standard level 21 Eladrin NPC "Ghaele of Winter" so a mage-like fellow.
AC 33 (+9 dex, +10 level, + 4 natural/armour) Fortitude 30 (+6 con, +10 level, +4 natural) Reflex 33 (+9 dex, +10 level, +4 natural) Will 33 (+9 cha, +10 level, +4 natural)
Attacks +25 (+9 dex, +10 level, +6 natural [+2 implement, +4 enhancement/natural)
Initiative +19 (+9 dex, +10 level bonus).
This Eladrin also has +24 to diplomacy, +16 perception, +21 insight, and its untrained stealth is +19 - meaning particularly for perception and stealth that it is more perceptive than your average scout trained and employed by the military (by about twice as much) and is twice as stealthy as a trained footpad.
Which would be okay, if the Eladrin wasn't a frostmage.
My point is this can be remedied easily by scrapping every things + half level to bonuses.
This changes the game from being a vertically scaling arms race of points, to one in which player character growth is horizontal (by gaining new abilities and cool stuff) and focused into the areas where the character is good. The difficulty class suggestions for tasks can then remain the same across the entire campaign, and not have to ramp up vertically to account for these ridiculous abstract bonuses. The barbarian who does not know much about arcana then does not get abstract bonuses to arcana because they got experience from killing things, that puts them ahead of apprentice mages who are are studying arcana. Similarly the bumbling professer-mage doesn't get abstract bonuses to stealth enough to sneak better than most of the footpads in the slums. Characters will get better at their focused areas, but not necessarily at everything.
Even if characters won't get as many points across the board characters recieve plenty of vertical bonuses (magic gear providing +2 to something, skill training, ability score increases every 2 levels, feats and HP),
Thus at level 15 the peasants struggle to hit characters, not because they have an abstract +7 bonus to defenses because "oooh they're level 15", but rather because they have more abilities, better equipment. Even if it is more likely that peasant mob can hit and damage level 15 PCs, this should just force players to be more careful. It has the added bonus of meaning that level 4-5 town guards are still a potential threat at high levels, if they bring they full force of the law down.
So philosophically there seems no reason not to do away with the +half level to everything, as this removes the ridiculous vertical inflation, which seems to fufill little purpose other than indicating that certain enemies are almost impossible for characters to hit at low level, and that certain low-level enemies can be autohit at higher levels.
It also ads sense of a game world scale and progression that does away with the MMORPG ridiculous vertical value increases.
The vertical inflation just does not seem necessary at all, when it can just be done away with.
Oh and the best thing is that doing away with it on EVERY BEASTY and EVERY NPC or PC means that hey, everyone is at the same disadvantage, so the higher level monsters and characters are working on almost the same to hit and AC values, as PCs should have awesome magic. It just brings lower level characters and monsters up a notch in their ability to do damage and perhaps bring down higher level critters.
So yeah, that's my rambling.