The only way execution tech would be great is if a returned one still counts toward the 'total paralyzation effect'. Otherwise as long as someone can return a high number tech then you'd never get the combo effect.
So far as damaging moves go I do not see even the low number execution techs as more powerful than the standard power shot designed to injure someone. There's no point to combo into them if you can't get all 13 to connect. If there is one execution tech you can't land then it's really no different than hitting someone with a standard power shot 12 times except the effect is likely significantly less (e.g. hitting someone's shoe is probably not as damaging as hitting someone's face).
That said even if the effects on execution techs persist even if returned, you can simply just dodge the high # ones instead. It's clear that they start off pretty weak so just focus on avoiding the weakest one so Tohno can't finish the combo. Yes Seppuku looks pretty strong but if you look at the way Tohno was using up energy it's certainly not a worse than getting hit by any decent powershot.
Stop comparing it to a Power shot Phantron.
The Execution Methods are just Tennis Shots that are made both, get points but injure the opponent at once.
Whereas Power Play shots are designed to overwhelm the opponent, where the score doesn't matter too much since you're just trying to overwhelm your opponent.
Power shots are meant to do you in in a single blow. These execution moves are clearly meant to torture you are the match goes on. For instance, these are the kinds of moves that would OBLITERATE endurance players like Kaidoh and Jackal.
I'm curious as to how that will be animated now. I'm still in shock everytime I look at that chapter page.
Gin was conscious before the shot touched him, when he landed in Kawamura and Kurobane's arms, us as the readers can't even be sure if he is even breathing properly.
Tohno is the only G10 member who is shown visibly tired in a match against a MS. Sure his partner probably is just chilling the whole time but it still implies using the high powered execution techs wears you out a lot. Given that G10 members are described as having unfathomably better base stat compared to MS, it is even possible you're trading stamina at a negative ratio (i.e. whatever damage you do to the enemy, you do more to yourself). For a point of reference, thus far all the high tier HS guys outlasted Atobe, the king of endurance, and often very comfortably (they're usually barely sweating). So the fact that Tohno gets tired playing two MS players who are certainly not known for being great at endurance means the execution tech tires him out a lot.
Now the high number ones he can probably use them forever but Marui had no problem returning/dodging those, so Marui isn't a top tier character at least not compared to say, Atobe.
I can see you use these techs if you've a game in the bag and you just want to torture the other guy, though I don't think you need any special techs to pull that off if you just want to beat up an opponent that's losing. Devil form Kirihara does that fine too, and presumably it can't be that hard just smashing the ball into someone's face repeatedly when you've total control. Yes execution techs lets you hit the ball to places other than the face for variety, but if you just want to beat someone up I think smashing the ball in their face works just fine.
The major problem I see is that it looks like the execution techs progressively uses more energy the lower number they go (you can see Tohno gets more tired as the numbers go lower) but aside from having different ways to splatter blood, it's not clear to me if tech #1 really does more damage than say, tech #8.
How do you know he was tired?
He looked frustrated and angry that Marui and Kite weren't a walk in the park but in fact good opponents. He was angry that he was going to have to bring out almost all of his Execution Methods on MSers.
Tohno didn't look tired. Nobody was tired, and Konomi would have had Kimijima state that Tohno was tired more likely.
Konomi never has somebody tired and then have a character not point it out.
---------- Post added at 10:40 AM ---------- Previous post was at 10:37 AM ----------
Remember that at no point could Kite and Marui attack together.
But notice that neither Kimijima nor Tohno felt like defending at all. They never once were worried about defending.
Note how Ochi/Mouri had times where Ochi said to recognize their positions, or times when they both retreated, since Atobe/Niou made an awesome pair,
Whereas Kimijima/Tohno just stood by the net and casually attacked. Then Tohno wanted to torture his opponent.
Err, it's rather consistent the amount a character is sweating is indicative of how much energy they're using up. As is with most manga being 'tired' doesn't even mean much because virtually nobody important has ever lost a game due to running out of energy, but the 'sweating a lot' shows they're at least playing the game seriously. For example Duke crushed Gin but is still sweating some and he said he had to go all out. If he can beat Gin while at 60% comfortably it'd show him not sweating at all.
While nobody important loses due to getting tired, it shows what Tohno did is likely his limit. To be fair he was basically playing 1on3 so maybe it takes a lot out of you.
We don't know if it was serious tiredness like you were saying. You suggest that the side-effects of the Execution Methods (EM's) are serious tiredness.
There isn't enough to suggest that.
Am I the only one that thinks that the Execution Methods should all be considered as a part of a single technique? I mean, we don't really see any difference between them (except the one that hurt Marui), in fact we see that they have a common final porpuse (the complete paralysis of the enemy).