One of the things that I really like about Original Edition Delta (Dan Collins’ restatement/mild reworking of Original White-box D&D) is how he adjusted the attack bonus charts for men attacking monsters to make a smoother progression as characters level up. The original chart divided Fighting Men into groups of three levels, e.g. 1-3, 4-6, 7-9, and then had the number you had to roll to hit each armor class improve by 2, 3, or 4 each successive category. I have literally no idea why Gygax & Arneson did it that way, unless it was desperation to save space in the tiny booklets. To make it worse, the instructions told you to rework the columns into groups of 4 or 5 for Clerics and Magic Users. Apparently they couldn’t even spare the space for two extra header rows! Though I’m not sure I’d have the patience to do much better with nothing more than a typewriter to do the layout.
I’ve been playing a bunch of Old School Essentials lately, which reworks this so that instead of a clunky chart, each character class lists its bonus to hit/THAC0 (for ascending/descending Armor Class), in a beautifully laid-out, easy to read fashion thanks to modern tools, more space, and a better graphic design sense than Gary had.
Unfortunately, it keeps the odd, bumpy progression so characters can go level after level with nothing improving except their hit dice or maybe spells for spell-casting classes. I found I really missed Dan’s approach to it, which ended up nearly the same place give or take a pip on a d20 at each level break, so I implemented a similar progression as a house rule in my game. If you’d like to do the same, here you go. Just replace the Thac0/Attack Bonus listed in the OSE Class tables with the bonus from the appropriate column in the following. Dwarves, Halflings, and Elves advance as fighters (in OSE every three levels). I tried to stick as closely as I could to matching the OSE tables, particularly when it came to the earliest level that the character got the improvement for their “band”, e.g. if a Thief got the +5 bonus at Level 9 I tried to preserve that.
Unfortunately, WordPress’ stupid custom html doesn’t show the table correctly except in preview mode, so I used an image. The actual sheet as a web page is available here, if you need it.