I love 4e as an engine, and its diversion from 30 years of same ol same ol canon. I wa sthe creator of the Rouseketeers, here! And O.A.F (old school admirers of fourth edition, lol) Eventually I also moddded it for simplicity and remove the grid/minis as we all prefer TOtM play..From the looks of it, In some ways I kinda 13th Aged 4e. But it ended up being alot of work modding powers, and especially adventure conversion, and it was not adding any significant fun factor at the table for the players. So I grudgingly dropped it, and instead added some things about 4e we liked to our OD&D S&W mashup.
But I would love to continue that 4e game if I had tonsof prep time. I can wing a 4 hour session of Od&D with not too much effort, not so with modern D&Ds....too many books, stats, etc.
We have started a DCC game recently, and it is proving to be a nice mix of modern sensibilites and fresh takes on classic D&D elements without the hassle.
Sorry for the OT.
I decided to move this discussion to another thread to not derail that one.
4e is a very flexible game engine (more flexible than WotC realizes or will admit). Modding it to be a simpler game that plays the same way just without minis and grids would take some work (143th Age would probably work well for this).
I go a different way with my modding of 4e. I go for really simple, either with generic powers or no powers. Here is a summary of my current iteration of a lite RPG using 4e's basic structure.
After some playing and thinking I have decided to ratchet back the complexity a little bit. Not that it was that complex but I want to eliminate encounter and daily powers. Those just aren't need right now. These changes will get this basic game more in-line with my original goal of a BX complexity level game using 4e's mathematical structure.
First I am eliminating AC, Fort, Reflex, and Will for monsters and replacing it with a single Defense score that is equal to level + 14. Spells will now get a proficiency bonus so that their numbers are on par with weapon attacks.
I have used different types of minions over the time I have played 4e and for this iteration I have settled on minions having HP of 5 plus twice level. With the targeting rules below this should result in most attacks that target minion groups dropping one or more minion with a successful hit.
The combat rules will be similar to the 13th Age combat rules regard to positioning. When you target monsters you can target one standard, elite, solo, or minion group. Excess damage from a minion attack gets passed to the next minion. For example, a group of 0 level kobolds would have 5 hp each. It an attack against the group does 12 points of damage then two kobolds would die and the group takes an extra 2 points so that another attack that does 3 points of damage would drop another kobold.
Spell attacks work the same as weapon attacks. With a spell attack you can target a monster or group that is engaged or at range. So for example,if you are a fire wizard and attack an engaged group of minions then you can narrate the effect as a burning hands spell. If you attack a group at range then you can say it is a fireball spell.
Both weapon and spell attacks do 1[W] at first level and an additional [W] for each three levels gained (i.e. 2[W] at 4th, 3[W] at 7th, etc.), and add the PC's level to the damage.
Armor is simplified to light (+3 to AC), medium (+5 to AC) and heavy (+7 to AC). Shields add +2 to AC and Reflex. Neither medium or heavy armor get Dexterity bonuses.
Now onto the classes.
Clerics can wear light or medium armor, and use shields. They are proficient with all one-handed melee or thrown weapons (they can add their god's favored weapon at the DM's discretion). They can make d6 radiant spell attacks.
Fighters can use any armor and shields, and are proficient with any weapons. Monsters need to make a hard saving throw (16+) to disengage from the fighter and cannot opt to take an opportunity attack instead.
Rogues can use light armor and are proficient with all one-handed melee, thrown, and light and medium ranged weapons. Rogues add 2d6 to the damage of any attack in which the target is engaged with one of the rogues's allies or is unaware the of the rogue's presence (this increases to 3d6 at 11th level and 4d6 at 21st level).
Wizards cannot use any armor or shields and are proficient with one-handed melee and thrown weapons. They can make d8 spell attacks and must choose a primary damage type that their spells do. They can change this damage type by reducing the [W] of the attack by 1. They can cast utility spells a number of times a day equal to their Int score plus half-level (remember ability score range from -1 to 4 for PCs). When using a utility spell they can use their Arcana bonus for any skill check.
All PCs can choose any 5 trained skills at 1st level and their are no changes to the non-armor defense bonuses and HP that each class gets.
This mod is pretty easy to do and lets me run things on the fly (like I do in OSR D&D). However, it has some significant change from OSR D&D. First, it eliminates the single digit PC, adds healing surges, has pretty clear and easy monster building math, has a unified skill system, etc. Those are a lot of the things I like about 4e (though I realize not every likes these things).
I still like regular 4e too but I like a simpler game sometimes too. 4e's basic structure gives me both. If I wanted more of a medium complexity game I could mod one using 4e but that would take more work and 13th Age fits the bill pretty nicely.
I would love to see what other people have done to mod simpler games for 4e.