I don't expect a D&D video game to follow all of the rules and math of D&D (but several have in the past, including all the best ones). But it shouldn't feel like Generic Fantasy: Origins with a beholder.
So what are the
correct rules and math of D&D? Back in the day, the lower your AC, the better. Starting with 3e, you want higher AC. Did the entire IP suddenly flip on its head? No, they are just a system for resolving a basic action: did the monster hit me and did he do damage? What are hit points? My mage in 2e had about 40 of them. My mage in the game Neverwinter on PS4 has about 98,000. But if a demon smacks the former for 20hp and the latter for 49,000, guess what? Both mages are down to half of their health and need to fall back and heal up a bit. Both games resolved the same exact situation with identical results. The numbers - no matter how vastly different - are just expressions of percentages.
Is every table across the world that is playing original D&D through 4th edition *not* playing "real" D&D because 5e is the currently supported iteration? The old dudes playing Greyhawk down the road for the last 30 years,
numerically, don't have anything in common with the 5e crew that gets together on Tuesdays to run the latest FR campaign. What about a 5e group that introduces a few semi-significant house rules? Are they playing D&D or are they playing
Generic Fantasy: Something-That-Resembles-D&D-But-Is-Not-Quite-Right?
If my wizard can cast magic missile or line up a cluster of kobolds to fry with a fireball: that's a D&D game
If my paladin can quest for a flaming holy avenger sword: that's a D&D game
If I can roam an enormous, sprawling city like Waterdeep and visit Khelben "Blackstaff" Arunsun in his tower: that's a D&D game
If I can ride a kank across the harsh Tablelands, guarding a caravan against attacks from elven desert-runners or packs of thri-kreen: that's a D&D game
If I can fly a silver dragon across the plains of Solamnia to halt an advance of Lord Soth: that's a D&D game
If I can take my chances with a Deck of Many Things, or confront Strahd in his castle, or lead a charge of knights against the forces of Iuz, well, I think you get the picture.
Why get caught up on what the
correct rules are for a great D&D video game, when you could never get two out of a thousand tables to agree exactly on what the right way to adjudicate a session is? Rules are kind of like the ropes and pulleys and dudes in all black that move stuff around during a theatrical production. They're just there to facilitate the story - the less noticeable they are, the better, yes? I don't care if a D&D video game has my characters cap out at level 20 or level 150. I don't care if their hit points (or, *gasp*, "health") hangs around 70 points or reaches into the millions. I don't care if the suit of platemail has a +5 bonus to AC or a +7,580 Defensive boost.
TL;DR - if the story is good and they make usage of all the iconic D&D elements - spell names, locations, famous NPCs, unique items and artifacts, and yes
BEHOLDERS AND MIND FLAYERS, I will absolutely give it a try.