One thing I kind of miss from DOTA (not enough to actually play DOTA, mind you) is that they put things in the game that were almost impossible for a normal person to do consistently. Like predictive shots on invisible people, fraction of a second invincibility frames on a couple abilities, or controlling multiple heroes. Being even decent at Visage or Meepo (two characters that gain controllable allies as part of their kit) is almost impossible, but that's part of the game's charm where you can become really fucking good at something that most people can't do*. Overwatch kind of lacks that. Where like fundamentally the difference between a grandmaster player and a diamond player is that the grandmaster player hits more headshots and understands the script better. They know the map knowledge and the meta, they know positioning, they know their character's role. But that's about it, and like honestly I think most people that use mic and pay attention could learn the script just by playing 50 hours at the grandmaster level (assuming they magically didn't get flamed to hell).
To provide an example of how OW and DOTA 2 are different, invisibility. Sombra's invisibility gives her a speed boost, and IIRC it doesn't disable transponder. The ability basically just reads "go wherever you want". That's why no one ever spychecks in OW, its a waste of time and ammo. DOTA 2 also has very powerful invis abilities, but in DOTA 2 you can get dust. Each use costs gold AND puts it on a long cooldown, but if you do catch the invis character you not only reveal them but you apply a slow. Missing with dust is very punishing but the way its designed is just begging to be used predicatively in a clutch manner. What the DOTA 2 design does lack is transparency and user friendliness, which OW has in spades.
I do think that OW's core design is fighting itself. The game is designed to be played 6v6 full tryhard. Playing it any other way can be super frustrating. Its a game that really wants to be about learning to get better. Yet the skill ceiling is fairly low and the developers keep lowering it. For example the way they nerfed Ana, they dumpstered her sniper style (which is the hardest thing about her) yet kept her tank healing aspect that is both incredibly difficult to counter** and incredibly easy to pull off. This after buffing her firerate because Ana was difficult, as if having a character low-level players can't use is a bad thing. An example of how the skill ceiling was always low is the flanker characters. Almost all of their abilities are automatic saves and automatic mobility. Predicatively hitting a Tracer is so, so much harder to do then it is to prevent, because her dash is designed to automatically save her. 80% of what makes Genji, Tracer and Sombra difficult is aim. The only character I actually had to work to learn mobility on in this game is Pharah, and low and behold they buffed her so the skillset I cultivated (that almost no one else was good at) suddenly became meaningless. I remember learning scout in TF2. You have to actually dodge as scout. Not just that, but there's all sorts of cute tricks you can use to parkour across rooftops and low objects like crates and boulders. Every hour I played in scout I got a little better at the movement. That's not true at all of my Genji, once I figured out the rules for what can and can't be wall climbed I was pretty much set.
*I was really good at timing based save abilities that targeted my allies or myself. Which is part of why I stopped playing, you can't save a carry who has no self preservation and the supports get blamed for all losses.
**To be clear, yeah you can dive Ana, but that's not a counter to the tank heal strategy. That's just countering Ana, she doesn't do well at all against dive. Winston and D.va can both make Ana essentially AFK whenever they want.