id like if you would represent my arguments fairly.

>Are you stating for the record that it is DnD for any character, with any stats, wearing heavy armour, to automatically succeed in jumping over an enemy and then land behind him and then backstab him?

No but im saying any dnd character regardless of stats, armor or class can walk around to the opposit side of his enemy with no roll required. This is RAW.
But thats not even my point. No particular rule or ruling IS or ISNT DnD.
DnD has had tons of editions, erratas, optional rules, third party content, homebrew and forks. Wether or not something is DnD isnt decided by wether or not it follows one particular ruling.
Otherwise very few genuine DnD parties would actually be DnD.

>Simple yes or no answer.
which i gave you at the very start of the post: yes to all. all of these things are DnD. Stranger things happened at gaming tables.
But the fact that you want a simpel binary answer tells me that you think in terms of a video game where such interactions are hard coded. We are talking about a video game. But DnD isnt a video game. Baldurs Gate is a video game adaptation of DnD.
In DnD, absoluteley all of those things can happen at any given table under a number of given circumstances.
>Is it DnD for the DM to say that every grappling attempt automatically succeeds as long as he has 17 STR?
Its still dnd, its just not an overly smart ruling.
but i prefer this over not beeing able to throw anyone because grappling hasnt been implemented like in any other DnD adaptation quite frankly.

>Save against damage.
Some things can be counterspelled. Some cannot. Theres guranteed damage from AoEs and auras and there have been for many editions.
If youre caught in an explosion theres also nothing you can do about it. Likewise, if youre standing in the middle of a barn filled with very flammable hay, and a goblin shoots a fire arrow into it, the only thing you can do about it is kill the goblin before he can fire the arrow.
This is the only logical conclusion to that scenario.
In my last session, the Priest killed a ghouls imply by standing next to him while surrounded by a fiery aura, which together with the ghouls weakness to the damage type resulted in its immediate disintegration without any save or AC allowed. I was quite bummed about it but it made sense.
> Is this how you play DnD?

This is how you play DnD.
I dont know if youve read my post in full but id like to direct you again to the paragraph about the Ten-foot pole.
"Cheap tactics" is how you play DnD. its how you survive. If you play by the rules, you die. Low level characters are weak and prone to getting knocked out before they can even get close to an enemy if they have low initiative.
Getting the drop on the monsters, surprising them, trapping them or otherwise neutralizing them without having to pray for Nuffle the dice god is exactly how you play DnD.
Your enemies will do the same. Honor is for noble knights jousting, not for mercenaries scrounging through half forgotten caves duking it out with the dregs of monsterous society.
In case youre wondering, google Tuckers Kobolds.

Or in case youre a weeb, watch Goblin Slayer.

>5 foot step action vs bonus action
it worked as a minor action in 4e and 3.5 so clearly thats not the issue
However in 5e the primary issue is that warriors arent sticky at all. 3.5 also had no solution for this mostly, pathfinder came up with some ways to do it.
Generally i think larian ought to copy the Mark mechanic from the Cavaleer class and give it to all martials (and battlemaster maneuvers too for good measure) thatd be a start. AoOs are a terrible way for melee characters to project threat especialy since withotu feats they are limited to one per round(rather than one per turnas in older editions, another stupid descision they should go back on)
im with you, flanking should be there, i still dont hate backstab because its somethign that i never understood why it isnt there to begin with. I think both of these should exist but as i said before, AoO should trigger upon leaving any threatened area opposed to leaving the reactors reach.
>Flanking optional rule
i forgot thats "optional" too in 5e. man i sure dont understand how people can play this game RAW. its so barebones.

>remove as a source of advantage
im not against that.
a flat +2 would be fine, thats how the previous edition did it.
The entire reason why advantage exists is because focus groups told WOTC that players were too dumb for basic math and that "players love rolling dice so let them roll TWO DICE"

>Shoving as a bonus action
i think its fine as a bonus action, implement proper grappling rules and the problem is gone.

>if you break concentration spells are close to useless
a matter of design.
I personally dont hate it because i think casters SHOULD be vulnerable. they used to drop in one hit by a goblin and for good reason.
If frontliners had better stickyness, casters getting mogged by weak enemies wouldnt be an issue.

So all in all i understand your points.i agree with you on some of them, not so much on others.
I think these dont need to be adressed one at the time, i think a good set of changes would make all of these points go away

>untangle disengage from jump (and give it a non retarded animation)
>Change how AoO works
>Implement proper melee rules (grappling, marking, one reaction per turn)