LOL magic isnt important to be flexible this is the part of the system that people first house ruled back in the day... nailed down like a trap its very hard to make ones own game world in face of the D&D spell casters.
No I think if you assume they will really accomplish next to nothing (aside from murder skills and spell casting improvement) that you dont assume already at low levels you are closer to the truth.Bounded accuracy keeps obstacles in scope upwards and downwards too.
I'm not quite sure how to parse the above....So forgive me if I got your position wrong.
Yes, I think magic is important (for D&D as a brand, not me personally) to be pretty much "locked in". Not only because so much of the game mechanically hinges on HP/damage, etc., but because of the "branding" effect of things like "Magic Missile" etc. I completely agree that it makes it hard to deviate too much when world-building...which was actually why I first left D&D to explore other systems.
The second paragraph...I just...erm...Bounded Accuracy keeps the rolls in scope, but the nature and scope of the obstacles which constitute a given DC is generally undefined.
The other incidentals will likely say incidental, the fact that the fighter cannot even match Olympic jumping distance without DM intervention...and can probably get to 20str early which is cool but if things are wired down and forced to stay realistic another 2.5 feet on your standing broad jump isnt going to make the character feel more awesome. Yeah not really
I'm not sure how you're getting this. There is precious little guidance on what determines DC on a Str(Athletics) check. The only jumping rules I'm aware of cover the cost in basic movement.
AFAICT, the GM at table is perfectly capable of changing what constitutes a DC 20 check based on level/tier, as well as (or as part of) their campaign feel. (Heck, toss in class there, if you want.) That may or may not be a fantastic idea overall, but it certainly is a dial that the GM can turn. The big difference, IMO, between D&D and Fate in this regard is simply that Fate has that dial in every direction, for every skill and action*. D&D, because of its more detailed, structured, and exceptional (wrt skill checks) combat rules, can only have that dial as a contrasting mechanism. Personally, that's a limitation of 5e, but overall, it seems to serve its market needs well.
*although, thanks to the influence of aspects and its other mechanics, it makes life easier on the DM.