And if it wasn't worse, then you might get other people disliking the idea that everything just works the same, just different labels to stuff that isn't very different at the end, what a bland game... WotC designers are trying to make the game interesting both functionally and narratively. Putting back some flavor and story into D&D is a major design goal for 5e. Still, none of us gets everything as we would like, neither functionally nor thematically/narratively. What you don't like, you have to change it up just like the rest of us. At least the options abound, and the framework is designed to be easier than ever to tinker with.
I'd like to be agreeable here, but I have to say, I am unconvinced by this, and I don't think this is a good example of "Well, we all have to change things!".
The issue here is that by making these assumptions, they narrow what D&D is about, rather than broadening it. You say they are trying to "make the game interesting" and "add flavour and story", and that's cool, but I don't see this doing either of those things. It makes the game more bland and trite, when Good Clerics do Radiant, Evil Clerics do Necrotic, and worst of all, Neutral Clerics choose. If it was Clerics of certain gods that did different damage types based on the gods, or if Clerics of the gods always did radiant, but those who worshipped non-gods (i.e. high-end demons/devils etc.) did necrotic, I would totally buy it as "flavour", totally, but that's not really how it is, at least from what we've seen.
As for "options abound", well, they don't, not with this, at least. If I want to change this I have to trawl through every single Cleric spell and see if they decided that it did follow this bland scheme, or didn't. I can't set a switch at a PC level or the like, because it's inconsistent (which is part of why I say lazy design). Not unique in an interesting way, just inconsistent, to be clear.
If the designers really think that sort of thing is what makes D&D "interesting" and "flavourful", if they think returning to "Death is EVIIIIIL!" spooky-trite-ness is a good thing, then I should be bracing for a real onslaught of really wishy-washy, weak-sauce fluff, I guess!
YMWV!
Let's have some REAL flavour - the Warlock sure has some. That's flavour. Not "Evil Cleric casting spells sometimes do Necrotic damage where Good ones do Radiant, no explanation given as to why".
EDIT - To be fair I still could be convinced that this is no big deal, if 5E actually has setting books AND those setting books immediately start challenging this kind of stuff, as they did in 2E, saying "Well that's not how this works here!", or if the DMG has a really decent chapter on how you can adjust this stuff (and does things like listing every spell you'll need to fiddle with), but I suspect that, as with early 4E, the mighty god BRANDING (TM)(R)(C) will mean that in the DMG they don't give good options here (merely hand-wringing briefly about how you could, maybe, I guess), rather hoping people just stick with the defaults and think they are cool. Then of course 2-3 years down the line we'll see a DM-oriented book which DOES give good options which should have been there from the start...