Part of it is just, 5e is a child of 3e (despite many statements about it being "AD&D3," e.g. an alternate successor upholding the Advanced line.) But multiclassing, underlying math, caster power, CR little better than intuition, flawed (both poor and OP) feats, and adventure/encounter pacing issues? That's most of the problems of 3e too. 5e is a toned-down version of 3e, for good and for ill. That ramps up the argument intensity, because we're still litigating the issues we've been hitting for 20 years or more.
And I think D&D should improve in those aspects. The game is more tolerable now then back then, but I do think the inherent problems plaguing the system needs to go.
This may be an issue then. I don't see it as "the dungeon-crawl game." I see it as "big tent," which includes crawling and a lot else besides. (Kinda surprised that you advocate so much for 5e-as-it-is though since, IMO, 4e being so well-balanced in combat makes it better for dungeon crawls.
Then it's a difference in perception. I felt like that was the case. It's not that I want 5e wholly as-is, though dungeon crawling isn't just about the combat. It's about exploring the unknown. Really, what you're able to do comes secondary to what you're able to find and what you do with what you found. So contributing is less about having something unique and meaningful in your statblock and more about what you, as a player, bring to the table.
Even apart from that, I'm skeptical. Damage and defense spells are still great. Many others (e.g. misty step, invisibility; borrowed knowledge or enhance ability; rituals like augury and locate object;, etc.) are still good, perhaps better in confined underground spaces (and those are all 1st or 2nd level too!) If the Wizard can be confident that normal staples like fly aren't worth it, that just means they can focus better on the spells that remain and are worthwhile--which doesn't really reduce their power.
In low tier games, the fact that they're limited resources make them more difficult to justify using. In high tier games, the wards and extremely dangerous traps make casting much more difficult. It isn't about spells not being great, it's that if they're used poorly even if they're generally good, that makes them difficult. For example, thinking the wizard can just cast invisibility and walk in the middle of the room without being
seen. That's a luxury at high levels because alot of monsters have truesight or blindsight.
How is that difficult to grasp? I care about it for the same reason I care about the design of classes in FFXIV--I play the game, I spend a lot of my time interacting with the community, I read and understand the statements made by the developers, and I advocate for the things I like and criticize the things I don't. What more do I
You don't need to justify it, I just was looking for an understanding. I suppose your passion for the system overall is what gets you riled up. That's something I can't really relate to. I tend to just pass over things I don't like. I'm not a fan of Pathfinder and 4e, but I don't really want to change much of what's in there because I recognize that it's for somebody out there, just not me. If I don't like it, I don't play it. Maybe the fact that 5e is so popular means that it's harder to avoid, but it doesn't feel like the alternatives have gotten less popular.
Maybe, if such casual play is so goddamn important, we should have more than one class to carry that weight?
There are a few options for casual play, Barbarians and rogues are generally casual friendly. More complex than the champion, sure, but it's more like something refreshing rather than a new subsystem.
I have done my best to avoid any such arguments, hence why I focus on the actual statements made by the developers (e.g. referring to D&D Next/5e as a "big tent" edition, the books explicitly treating the classes as peers) or on abstract principles of game design (e.g. "how should a cooperative game be designed?") That way, I literally cannot be putting anyone down.
I think what they wanted in playtesting is different than their philosophy now. But also, your philosophy for game design doesn't necessarily have to be the same as others. I get that some people don't want to play "tails" from sonic, but some really do want the enjoyment of being present without the consequences or stress of being highly skilled at the game.