Let's not. The accusation was leveled the moment the PH1 was out, and it was refuted, from the PH1. Case closed. It was false - most charitably, an example of ill-advised or ignorant hyperbole.
I see no closed case. I see someone who set a very narrow parameter (no arcane spells in the PH1) and then ignores books that came out only a few months later that proved him wrong.
When we go behind the hyperbole and look at the remaining claim, the one you repeated, above, that the /presentation/ made powers merely /seem/ samey, you have a much more subjective, and thus not strictly falsifiable claim.
But, it's, once again an inconsistent one, because many things in D&D have been presented in the same format, before, without complaint.
Yes, yes I do have for exactly the reasons you /listed/ in slashes.
A fighter in 4e cannot cast ray of frost with his (nonmagical) longsword. But it doesn't matter; the fact is he is using the exact same mechanical expression. That expression makes it look (at a mechanical level) like the same thing.
Just for one of many possible refutations: No fighter power is subject to Dispel Magic.
By that logic, neither is a druid's wildshape. Complete natural and mundane ability, right?
But, rather than circling the edition war merry-go-round of proving your statement false, and you re-hashing it in a different form in the hopes of finding one power it's true for, let's take a huge leap, and assume, for the sake of the current discussion that you're right. That Fighters actually do have plenty of implement, area, powers that create zones doing typed damage that can be Dispeled, and that some of them even have the same names and exact same write-ups as some other classes use.
Two classes or more sharing abilities that have the same presentation, same name, and same mechanics, are nothing new to D&D, yet they've never led to calling those classes 'samey' before, or since - with the sole exception of the Sorcerer & Wizard sharing virtually identical spell lists, which caused a pretty minor stir.
Again, if you had any more strawmen I'd think you ran a scarecrow business.
In 5e, a battlemaster fighter makes an attack roll (using the regular combat rules, including picking Str or Dex to hit) and then spends a superiority die to create an effect. A wizard uses a spell slot to create a magical effect and forces the foe to make a special ability check (called a saving throw) against the effect. These are two very different styles of mechanical resolution, no?
In 4e, the fighter uses an encounter power (using the power to determine what ability score to hit with) and then does the effect as described. A wizard uses an encounter power to create a magical effect that requires him to roll to hit (using the same power resolution mechanic as the fighter, swapping Int for Str and AC for, say, Ref) and does the effect as described. Very similar, no?
This similarity of how martial and magical effects resolve create sameness. There is little difference mechanically between spellcasting and non-spellcasting attacks, save a few keywords and limitations. Since all classes shared the same bonus (1/2 level), same ADEU power structure, and same power resolution mechanic, classes felt too similar compared the very different styles a fighter and wizard played as under 1, 2, 3, and 5e.
And, we are left with another of these preplexing inconsistencies.
There are none so blind as those who refuse to see.
Either way, history was on my side. Come 2010, ADEU was being experimented on (see Psionics, Essentials) and the one-size-fits-all system was abandoned come 5e. I'm satisfied.