No.
Starting roles. You have the tools to be a defender or leader etc. You can always get other tools as you level up. You are no more "forced" to use them than you are forced to heal people as a cleric in 5e--even though absolutely every cleric knows, and can prepare, healing spells. Nor how a Fighter is
forced to use a shield because they know how to use one. I know that the "roles are straightjackets" thing is quite ingrained, but it's as false today as it was in 2007.
Okay. Name a class in 5e that can dual-wield "effectively." Because the only one I know of is rogue--every other class, you really want a shield or a 2H weapon, because that's where all the damage is. For anyone that isn't a rogue, including rangers, it's mediocre
at best past 5th level. And, as
@deganawida said, in 4e there's also Tempest Fighter, but further, there's Whirling Barbarian, and both the Rogue (especially if using hand crossbows) and the Assassin very much benefit from dual-wielding.
How is that not the case for PHB classes in 5e--or 3e, for that matter? Choose Dex or Strength, for example (and usually Dex, unless you
have to use Str.) Choose sword-and-board or two-handed. Etc.
Er...what? Not if they're actually designed to
do things. MM3 on a business card is for
basic monsters. The absolute bare minimum. I don't even know how you got this.
It isn't "10 levels stretched over 30." And frankly I find your characterization of level 21+ being "anemic"
hilarious, considering that the design of characters at that level fully expects that you'll frequently
die once a day. That's literally why Epic Destinies have features that trigger when you fall to 0 HP. They might as well openly say, "Once per day,
when you die..."
The one and only complaint you've made here that actually lands is the grind--and WotC agrees with you! They addressed it with MM3. Which, admittedly, is rather a long time to wait for what should have been the rules from the beginning. But it was, nonetheless, addressed.