Apropos nothing, here are my favorite changes to DnD systems. I put in parenthesis some systems that do this.
- Unified XP. I don't mind different XP per level for different classes, but I like having a single table. (DnD 3.x)
- Unified Saves. No Death Ray, Paralyization, Spells, etc. split that just got confusing. I like either the fully merged approach (Sword & Wizardry) or the three-fold approach (DnD 3.x). One number is easier, a three-fold approach gives some variety, so you know to use Will-based attacks on thieves and not on wizards, say.
- No Alignment. Honestly, it's just something I put on my character sheet and then try to justify later. I don't enjoy having it around, and I've played too long in a game system that lacks it. (Basic Fantasy Role-Playing)
- Unified bonuses. Much like how B/X D&D does it, I like that stats 13-15, 16-17, and 18 are the break points. I like how 5e does this, too, with its cap at 20. You get a steady climb without the craziness of ST 18, 18/01 - 50, 51-75, etc. up to 18/00 and then 19. Or Stat X giving a bonus at 15 and Stat Y giving no bonus.
- Ascending AC. I find this much easier to deal with. Give me a bonus to my 1d20 roll and then I can tell you what AC or less I hit. Very easy. (Swords & Wizardry does this, as did DnD 3.x)
- Weight not Encumbrance. Just tell me how much it weighs. How annoying it is to carry is a separate issue, and it's hard when systems combine and conflate them. (Swords & Wizardry) Ideally, the weights will be correct (cough, cough, my 10# one-handed sword in S&W).
- Unified dice mechanics. Not a lot of systems do this to a sufficient degree, but I like rolling in one direction - why is a 6 great for initiative and damage on a d6 but terrible for opening doors? Why percentile dice for locks but d6 to hear noise? The more DnD based games go for "roll high is good!" the better, I think - it makes it easier for me, as a player, to parse the results of rolls.
How about you guys? What rules changes do you find especially pleasing, easier to play than the original, or otherwise make the game smoother and better?