The discussion so far is pointing directly at "5e with a new coat of paint." Abilities the same, ACs, DCs, saving throws, proficiency bonus. You're on well-traveled ground, to put it mildly.
As an example of steering away from another 5e, take a look at my
Core Rules Module (click) here. Once you're over the irony of the use of the "Core Rules" choice of words, you might find:
- Rule Zero. Yeah, so far, so D&D. Or any RPG.
- Rule One, campaign theme. Typical RPG, but D&D sort of imposes its own theme.
- Rule Two. The GM rolls a d20 too? There's a D&Diversion.
- Rule Three. There's no Succeed or Fail. NOW we're diverging from a lot of RPGs, not just D&D.
There are many more diversions in the next 80 or so rules. But my point is that not making another 5e starts at ground level. Using 2d10 to resolve conflicts is cool, but it will take a bit more to break out of The Shadow Of The World's Greatest Role-Playing Game.
I guess I phrased things poorly on my end. My goal is to make sort of a hybrid of 5E and OSR material, similar to how Five Torches Deep doesn't claim to be specifically OSR, nor is it completely a reskin of 5E, it borrows bits of both.
At the moment I'm using the ACs/DCs/Saves from 5E so that I have a template to convert monsters and other challenges to work within this system. Proficiency bonus is done away with, but at the start of the game you do have the ability to make your character with the same stats as you would get with your starting class in 5E. The divergence is that if you want to put stats all over the place, instead of having the standard +2 prof. in specific skills, weapons and saving throws, you can totally do that. The other thing with this rules set is that skills are no longer tied to ability scores. There are six categories of skills broken into two descriptive words. It works like this, the GM can call for a skill check or the PC can propose a skill check, naming one of the 6 skill categories, the player then gets the option to come up with a creative way to incorporate one of their ability scores to add to their skill bonus. For example, a player is in a new city, and the group as a whole has experienced several cities prior to this one. That player wishes to search the city for a black market, but their Awareness/Insight skill isn't very high. They propose an Wisdom (Cunning/Subterfuge) check to the GM. Their pitch is that they want to use their gathered experience from other cities to help them find familiar signs that might lead them to the black market. The same player could also use Charisma (Cunning/Subterfuge) to slyly ask the locals of a nearby and shady tavern for information that might lead them to the location.
Another divergence (and yes I understand there are problems with this currently) is that there are no damage dice. Hits are one for one. This also results in the fact that you do not roll for hit points, each character starts with 2 points of a primary HP equivalent and 1 point of a secondary HP equivalent, and they gain an additional 2 points of primary HP and a varying amount of secondary based on class. The problem currently is trying to factor in the concept of resistances and halving damage. Although I'm not sure those two factors are entirely necessary overall. A barbarian's rage is also affected by this as well, and I'm still working on that.
Inspiration is also done away with in this system and replaced with a pool of d4s that you can acquire throughout sessions. They can be rolled to increase your likelihood to succeed on ability checks, attack rolls and saving throws (no more than 2d4 per challenge), or they can be used in other ways. Each player will start the game with 1d4 and will have a maximum number of them that they can have at any given time. There is a list of factors that allow you to gain these dice, and they will be available on a separate sheet that you can print out and leave in the center of the table which will also contain a list of all the actions you can take on your turn. The d4s are left in the center of the table and when a player meets a requirement, they simply take a d4 and add it to their pool. These dice can also be granted to players similar to how inspiration is awarded in 5E by the GM.
This system also utilizes equipment slots as well as two forms of encumbrance (one is standard, the other is more complicated and optional). The equipment slots diagram on the character sheet shows you what you have direct access to (which costs one action). Anything in your backpack costs two actions to find and use. In regards to your backpack, this is where the standard encumbrance rule comes into place. There is a section on your character sheet showing your backpack's contents. If at any point you do not have room to write anything else in this section, you simply can't carry it and must discard it. Along with this restriction you cannot carry more than 1,000 coins total. There is also the optional rule that items have a unit value of weight and your character can only carry a number of units equal to 10 + your STR modifier.
There are other interesting changes made as well that I will probably share at some point but keeping with the subject of this thread I don't wanna go off on too much of a tangent here.
