Correction:
- In 4e there were actual defined class roles that encouraged all classes to be good at something without being good at everything, normally backed up by a class specific mechanic.
- Not having the name striker hasn't changed the barbarian from a raging monstrosity that hits people hard or the rogue to be a sneaky trickster that can't tank and can't heal and not having the name leader hasn't changed the expectations of the cleric to be a healbot.
- In many cases the roles inspired a worthy new class. You can play Invoker-style bringer of divine wrath with a cleric in 5e but they are nowhere near so good at doing it and on any given day you could get up and decide to be a healer that day
- In still other cases the structure inspired a relatively worthy focus that when the classes were winnowed down could fold into another class but probably wouldn't have been invented if there was no encouragement to push the boundaries. The warden is a good example of this - if you don't consider class bloat to be an issue (or don't until it hits 3.X levels) then it's a worthy enough class, but if you value keeping class bloat down then the Paladin of the Ancients covers much of it.
- 4e class customisation was much greater than in 5e for pretty much anything except the Sorcerer and the Warlock (where two Sorcerers can have entirely non-overlapping spell lists and two Warlocks can share no spells and no invocations). Subclasses were there in 4e. And it's entirely possible for two monks or even two fighters to move completely differently and only share the basic class feature that makes the class, almost never even making the same attack.
I disagree with both of these points.
Twilight Cleric and Bladesinger Wizard are two classes off the top of my head that go against the trope of the typical cleric or wizard and are VERY, VERY good at it. Once she hits mid levels a bladesinger can tank better than any other class except arguably a Barbarian and she can even do it better than a barbarian if we are talking about multiple fights in a row that happen without healing or if the enemy is hitting with something other than bludgeoning, piercing or slashing.
If you expect your cleric to be a healbot it is because you are entrenched in a mindset that is not consistent with the current rules. A divine soul sorcerer is a better "healbot" than most clerics are and better than many celric subclasses can be. You can build a cleric to be a better healbot than a DS sorcerer, but it is not common.
A Mountain Dwarf, Hill Dwarf, Tortle or Githyanki Arcane Trickster Rogue absolutely can tank, and do it very well. You would do it through different builds with each - hill dwarf would max dex and con and depend on hps, mountain dwarf or Gith would go with a 14 Dex and half plate. Consider a hill dwarf Rogue is averaging the same hps as a fighter with the same con.
A Tortle Rogue can even dump dex because he has an 18 AC right out of the gate that after 3rd level he can pump to 23 with shield several times a day. This is a totally viable build - forget stealth, take expertise in thieves tools and athletics, round out skills with perception, investigation and insight plus your background skills. S16,D8,C17,I13,W12,Ch8, resilient con at 4th, 20 con at 8th. Wield a Rapier so you get strength-based melee sneak attack. Have some daggers or darts to throw that you can get SA with strength when you need to make a rare ranged attack.
All of these get into position faster than a fighter or barbarian tank because they can bonus action dash. They can use uncanny dodge to cut damage in half once a turn. The steady aim feature works really well for a Rogue tank since the idea of a Tank is you won't be moving much. Expertise in Athletics or Acrobatics also means it is more difficult for the enemy to shove or grapple themin melee as compared to virtually any other class that could be put up there.
4E customization was much worse than 5E and you had to fit your character into specific little stereotypes and roles, with little room for real customization.
