Let me be clear, the Gygax worshippers are far more annoying than the Arneson worshippers, but both groups are stupid to be kneeling at the feet of dead guys, neither of which knew how to successfully defend their stake in their own intellectual property. I'm going to say something that goes against the majority of the OSR kingdom but it has to be said:
These were not smart men.
I mean, they weren't any smarter than the average wargamer. I'm not saying they were idiots, but they were definitely not the "secret geniuses" that their worshippers would have you believe. Talking with a Gygax or Arneson worshipper should smell fake and a bit culty because it's false and those that unabashedly worship Gygax (or Arneson) are a cult.
Regardless of what anyone says, OSRIC (2e) is a better game than AD&D1E. It's easier to read, easier to generate characters, and generally a better reference guide in all ways. What you lose is really less than nothing, what you lose is... bad design from the hand of Gary Gygax.
OSRIC omits the Bard, Monk, and Psionic classes. The weapon vs armor table. These are all sane, rational changes as the original systems were cumbersome and pointless or completely antithetical to D&D's basic assumptions.
The 1E bard is a ridiculous multi-class puzzle to put together with such a tiny amount of legitimately rolled characters that it's not worth wasting the words describing the class that pretty much nobody will ever qualify for and therefore will never play. It's exclusion improves OSRIC for this reason as well as the removal of a basically unheroic class. The Bard was never a good idea for a dungeon crawling game where silence in a dungeon is an important thing. But that's for low-level adventuring, at high levels, there's no reason for a bard again because at that point, characters don't really adventure anymore. So the 2E bard makes a modicum of more sense than the 1E bard, but both suck at onset and at the core of the purpose for the class.
The monk is simpler to discuss - it doesn't fit the early game pseudo-european dungeoneering aesthetic, and it doesn't fit the late game domain play endeavors. It's a class that doesn't need money, weapons, armor, or magic in a game that propagates all these as a center of the play experience. As I mentioned before, the monk's far-eastern-asia nature also sticks out like a sore thumb.
While psionics have a place in some settings, not in the core of the game, they are completely abhorrent when sat next to a magic user or cleric.
The weapons vs armor table was probably the dumbest thing for two reasons, the first is there is no baseline. No weapon sits at 0s across the board. So there's nothing that compares it to. There's no armor baseline either, but that's less important. The standard Sword comes close, and in a perfect world it would be the standard, but it simply isn't. The second reason is that it adds a layer of abstraction and additional table referencing and math on top of a layer of abstraction and table referencing with close to zero consequence.
