1. Kotal is not really that execution heavy, and that's okay. Let's just not get too ahead of ourselves in the comparison to Kung Jin. The only thing I can think of that took me longer than my first try to execute was the triple f2 combo, which I hope for your sake isn't your go to bnb as f2 is pretty slow on startup (good as an anti air though). Coincidentally, I don't think Kotal's as good as Kung Jin, whom I agree requires less technical skill. Which brings me to my next point.
2. Execution level does not imply a character is good or bad. MK9 Kenshi, Aquaman, Green Lantern, MK9 Kung Lao come to mind. Leaving me with this final note. A character that has more options is better, which typically coincides with execution and having the know how to use said options, but the two are not the same thing. Kung Jin has more options than Kotal, so even though Kotal's f2 combos are harder to land, Kung Jin is a better character in me and many other people's opinions.
3. Having a "good" character doesn't guarantee you'll win, and having one who is "bad" doesn't guarantee you'll lose (except for Jade
). Still gotta know matchups, how to exploit every option against every character with yours, optimal bnb's and setups, good footsies, etc. That's how you see characters who are not perceived as good like Reptile making top 8 at EVO. That guy came prepared for the typical Summoner Quan, Thunder God Raiden, Tempest Lao, Outlaw Erron Black, you name it. Those people did not come prepared for Noxious Reptile, as hardly anyone was using him. I tier whore at least a bit in every game for the last four years and I still lose more often than I can win outside of my living room...to people who don't...Q_Q
4. Kung Jin is not being played as much anymore because he got nerfed, so a lot of players dropped him for Tempest Lao, whom I admit requires a higher amount of execution. But more importantly than that, he's got safer offense, higher damage and better mobility. He also isn't free to delayed wake up like Kung Jin can be when going for those mixups on knockdown. Kung Jin isn't bad though, he just isn't perceived top 5 anymore like he used to be. Which isn't a bad thing either.
In short, imo, execution is an inhibitor to victory that must be overcome, not a friendly helper. Reads, mixups, footsies/spacing, crazy frame traps that break armor, high damage and/or mobility are things you're going to want to win in this game. I prefer to respect people for winning, not for what character they use to do it. If I can't win when I think someone is laming me out, that's on me for not learning how to beat that.