I think that this argument leads to a very weak core, with as little flavor as possible to it, so that there's nothing built in that leads away from the playstyle that you see as the heart of D&D. Is that what you're looking for from 5e? (This is a genuine question, not some weird leading rhetorical thing. I'm legitimately curious about what folks are hoping for from the game.)
Yes, although I don't think that means it's weak or flavorless.
Not weak meaning the core system should be mathematically robust with enough wiggle room and the correct granularity to allow the desired degree of tuning.
Flavorless is impossible unless the core system includes no spells, magic items, races, weapons, monsters, etc.
I think there is a misconception (although it could well be me who has it) about what the core/module thing means.
To my mind the is no such thing as an "all options and modules off" character. There is one that uses the "Simplified progression" module, but that module is no more or less core than the one with 3e style feats or 4e style powers. It's probably the first module presented, because it's the easist to describe. It does not represent the baseline others grow from either. It grants simple bonuses that average out to about the same power level as the other modules.
Remember the goal of 5e isn't total campaign customization in the hands of the GM, it's playstyle customization in the hands of the players. Those modules are what you choose to help build a character that works the way you want it to work. They are not golden pools of awesome for your GM to hold mockingly out of your reach.
Some things will be in the GMs hands. If he doesn't want to use grids and minis he won't. Some things are in his perview, like magic items, but you should have a say. Some thing should be determined by the table before the campaign begins. "Will we use Vancian magic? Steve hates martial dailies but I really want to use that "Strike of the Happy Walrus" power."
Sometimes it will matter, if your GM has a very specific campaign world in his head he might say "All arcane magic is Vancian only. All Divine magic is point based. Psionics exist but to regain power points you have to eat a puppy, and I mean YOU, the player." And if you wanted something he outlawed you'll have to take it up with him, just like always.
For the generic game? It won't matter a whit which modules you use to build your character as long as you have it all on your sheet when the dice start rolling.