Since the OGL debacle started it seems very fashionable to create your own rule system, and I'm one of them. To my defense I did start my "MeyerHawk House Rules" project before the rumors came out from WotC HQ. My ambitions in the field of game design are modest. Designing rules are not my speciality, so making a rule system for general use are way beyond my intent.
What I want to create are a set of rules that works for me running my games for players who likes to play in my campaign. Not a new set of rules, but build on an existing rule system. Before the OGL debacle started my intent was to base it on A5E - Level Up from EN Publishing. Then came the uncertainty with the OGL turmoil and I put my project on hold. My goals for this projects are to share my rules with you, without running into licencing issues. Thankfully it is probably safer to do so now than ever before.
Time to list the goals for my house rules
I want to mess around with some aspects of the rules, but it need to "feel" like D&D. Based on the D20, use AC, the same six abilities, hit points and the other terms familiar to all D&D players.
5E rules have become a new standard for D&D games, with many more or less compatible systems available or in development, so to be compatible with this ecosystem is the best way forward. With compatibility my plans are not to make my own 5E clone, but to be able to use 5E monsters, spells and items with very little tweaking. Also for the same type of content I create for my campaign to be useful in any other 5E based game without much conversion.
When you make a RPG system for publication you make it for an audience large enough to make it a profitable endeavor. My goal is to tweak 5E to suit me and my players playing in my Greyhawk campaign. This will remove a lot of the constraints, opening up for a system of rules for more advanced magic, divine workings and planar interaction.
The biggest change I'm working on is to abandon classes. Why the heck get rid of one of the pillars of the game you probably ask?
Two main reasons, the first is to emphasize the "setting view". Meaning people in Greyhawk would not think or talk about themselves as having a "class" as in the rules, people would describe their jobs, position and what they can do. You can be a warrior, a knight or the Order, or fight for something, but that is not something that should be constrained in game mechanics.
The other reason to abandon classes are players and stories. When you start playing a character and you want to be able to cast arcane magic, so you start playing a Wizard. Twenty sessions later your interest in arcane magic might have vaned, the story taken new turns, and you want your character to develop in new directions to follow along, or to thwart a villain using other means.
I want the desire of players and the story to guide the development of characters, not a course of advancement set by the rule book. Character will be able to learn new things by spending XP and making a Learning Check. Learning things your character have experienced or can find a teacher for will be easy, other things harder and will require time or adventuring.
Another side of things are the GM - Player work load, and I intend to place a bit more of the work on the player. Having players roll more of the dice and doing a bit more of the math. This will both speed up the game and keeping the players more invested and engaged, I hope!
Numenera introduced some of this, and that inspired me. I intend to keep the math the same but to shift the "burden" on to the player. For example: use a Defensive Roll instead of enemies making Attack Rolls. A character who has an AC of 16 makes a d20+6 Defense Roll against a DC 15 Monster attack, for a monster that has +5 to hit.
This way of doing things opens up for options geared towards this way of playing, and I'm more and more open to players making almost all the rolls, like perception. It is cool when players know they screwed up a perception roll, or are sure they made a good check. I have enough to do during games anyway, and to spread the workload more evenly is a good thing I think.
This is more subtle but a very important part of any RPG, keep it playable and fun all through long term campaign where the characters advance. The various D&D editions have had built in "sweet spots" or ranges where play was fun and not bogged down with too much crunch. Usually that have meant that play from around 3rd level to 10th or so have been great. Lower level play have had characters too feeble and higher level have meant way too many die rolls and complications.
5E have done a good job with this already but I think there are a bit more to do in this area, like giving low level character more hit points, introducing a +1 Proficiency Bonus to extend low level play. For high level play I want to see if it possible to create a formula to emulate multiple attacks using only a single attack and damage roll.
A more advanced system of rules for how magic, divine and planar aspects work in the world will add depth and new challenges for high level play. The important bit for these rules are that they have to work more on a "story level" and less on the mechanical level. Die rolls and things to keep track of should be kept to a minimum, like aspects to spellcasting only coming into effect when you go to strange places or angry you god for example.
Giving players more to do during sessions give me more room for rules and principles for how the world works that I can use both for world building, adventure creation and during the sessions. How gods and magic works are two examples of this. I' will present more as it gets developed.
I think we are all ready to move on after the "OGL troubles" having learned a lot about the importance of openness and licensing. I've used Creative Commons for my Greyhawk related stuff for many years, it is great to see it is now being used more broadly even by WotC. I intend for all my house rules to be released under CC -by 4.0, meaning it can be used for anything including commercial use. Only mention me as a source for it and you're good.
I'm using Obsidian.md for my games, to manage both my rules and all the other campaign notes. It is using markdown, and can easily export to PDF and HTML. I'll present my rules tweaks in blog form and as single article PDF's at first. Bigger compilations of rules requires more work, both in the form of editing and play testing so they will take more time. House rules are by nature in more or less constant development, but after an initial period of playtest will hopefully be shareable.
Hopefully some of my rules will appeal to you and be useful in your games!