I don't disagree, exactly. Like I it's a quibble, but I maintain that the breadth or range of options isn't any less in 5e, might even be more. Maybe I'm not putting it well.
How, 'bout, just how different can two characters be. In 4e a Slayer and a Mage were pretty darn different. Even if they were the only two options, they still wouldn't seem narrow, since they're far removed from eachother. In 5e a Champion and a Transmuter, say, are even more different from eachother than that. There may be plenty of things that'd fall between them that you can't do, but it's not narrow.
I get what you're saying - we're just using
slightly different versions of "narrow/breath of range".
Following your definition, you're quite correct. I'm using "breath of range" as "number of concrete different things". All this being said, I'll stop arguing.

At this point we're both looking at a sunset and arguing about the shade of orange it is. But arguing to argue is a pretty fun thing - so I'm doing myself a good deal of violence here.
Re-fluffing cuts the the game a lot of slack as far as being what you can do.
You can't cut it the same re-fluffing slack? 5e might mix fluff and rules a bit, but nothing insurmountable, especially if the DM is willing.
Perhaps I'm not "getting it" - but I find the 5e fluff a bit to "tied-in" to be malleable enough for my purposes in
this case. As an example : Fey =/= Fiend and it has some non-negligible impact in this game, so simply refluffing the druid summons hurts a bit, and stuff like this. It's nothing MAJOR, it's just little hang-ups in just a bit too many spots for my comfort.
This may be begging the question, but isn't 'what you can do' also subject to a conceptual level, thus allowing re-fluffing like you did with 4e? So your Druid isn't exactly a druid, and shortchanging is a form of summoning in which you trade places with the summoned animal until it's dropped, for instance... (that almost makes more sense, actually).
Perhaps it could work, I'm just... I don't know... I doesn't seem to
fit for me.
Examples are better :
My initial (3.x) mechanical concept was : basically Pokemon (but with demons/devils - so it's cool)
For this purpose, I had custom spells I built for my character in 3.x and got the ok from the DM. I wanted to have
summon X spells at every spell level and with the proper theme:
- single fiendish goblin summon
- couple fiendish goblin (or one "orc")
- "battalion" (4 I think) of fiendish hobgoblins
- fiendish ogre
- fiendish spitting drake
... and so on and so forth, all around the theme of summoning "components" of this "evil devil/dude's" infernal army
When 4e came around... at first I pondered...
a lot. But then I figured that I could use "lasting spells" and refluff my recast as the strain of trying to maintain the original spell.
So
lightning pillar became my conjuring of a lightning based demon that was extremely hard to control (hence, I could only allow it to strike at those that came to close).
scorching blast became the same kind of thing but with a fire demon that could teleport, etc.
The encounter spells were viewed in the same vein. The dailies were obviously not problematic. I played as a form of "lazy-wizard-lord-to-my-own-"summons""
kinda. I was pure battlefield control. But it worked and played fairly similar at the table and outside combat, I had the same
kind of skills and options as I had in 3e. And, bit by bit, my character
became my 4e character. So the transition is from this "version" as opposed to the 3.x one.
In 5e... as a wizard, the kind of powers I wanted to use were sort of "locked behind a 1 minute cast". Other spells worked beautifully for my concept (
flaming sphere is a prime example.) But on the whole the wizard wasn't a great match (there's a whole thing about my familiar that required 3 levels of warlock - which works on most levels, but then removes options I had already used in the game because of the drop in spell level access.)
The druid is the best mechanical fit - but there were issues with the refluff/houserulling that didn't pass the DM check.
It's not that I can't have my character in 5e
at all, it's that I can't have my character without ~2-3 (I admit simple) houserules. But, in this case, that was 2-3 houserules required too many for this game. And since I tend to think of an edition as being what is presented in the books, I don't assume particular house-rulings are available in all games (case-in-point: myself.)
... wow that was a lot of "not very useful info"... here's hoping it conveys where I'm coming from.