I'd like to start off getting right into what I've done/am doing/want to do to the game, but I first thought I should at least give a shout out to what I'm using as a base.
Fantastic Heroes & Witchery
Click the link, download the free version. If you like what you see, throw him some money and purchase the fully bookmarked pdf, or buy a dead-tree version. Or both. Whatever works.
Fantastic Heroes & Witchery (known as FH&W for the rest of the post) is a pretty solid version of D&D. It's not a retro-clone, as it doesn't really emulate any specific edition of D&D. Instead, it does a good blend of every edition (except 4th since it was such a huge deviation from what D&D is and doesn't really play well with the other editions). Its got the simpleness of Basic, the "feel" of 1/2e, and some of the fancy doodads from 3e.
All while still feeling like a coherent game.
This is kind of what I wish 5e had been. But it exists, so I don't really care who made it.
The game uses the universal modifiers of Basic D&D, and has all the standard PC races and classes (plus a few extra) for Traditional Fantasy (human, elf (wood and high), dwarf, halfling, fighter, wizard, thief etc) as well as different take on Tieflings. Each of the races has a stripped down set of racial abilities (from 3e at least), BUT thing I like about the racial abilities if FH&W is that they really only take into account the "genetics" of the race when determining abilities and leave out cultural/training based abilities. Elves are not automatically better with bows/long swords. Dwarves are not automatically good at killing greenskins.
Some of the classes are a named different (the cleric became the friar, paladin became templar) and most of the classes are a little (or a lot) different than in traditional D&D.
Along with Traditional Fantasy races/classes, FH&W has a section for "Weird Fantasy". These races/classes are to emulate sword and sorcery or sword and planet or most other adventure pulps. Races like reptilians, ape-men, earthlings, witchlings, and tainted. Classes like the Occultist, Necronimus, and others.
Other than some changes to races and classes, most of the rules are pretty standard D&D, with a strong influence of 3e, but stripped down and simplified.
My longest running campaign was an almost year long Pathfinder campaign that sadly ended in some terrible rolls and a TPK. After that, I was burnt out on all the STUFF going on in Pathfinder, despite liking most of the system. FH&W is what I've been looking for. Enough crunch to have some weight, but not enough to crush me.
This is a SUPER light "overview" of the system. I've left lots of stuff out (its a pretty long book even though it doesn't have any monsters or magic items in the book -- it assumes you'll use whatever you want for those and make it work - any old school monster manual will work with almost no changes), but I plan on going over pretty much the entire book in future posts as dissect, dismember, and rebuild it into my ultimate goal for what I want in a fantasy RPG...which I'll get into later.
Oh! One last thing for this post. Some of the writing in FH&W is......rough in spots, some of the grammar is off and some sentence structures get massively overused. It doesn't detract from the rules, but it is annoying.