Well I didn't use the term "break" the flow of the game, because that's how the game is supposed to be played. However, I said I don't like the flow of the game, because of the combo breaker system and the focus on it. I enjoy the neutral game a lot more, and a heavier focus on footsies and ooki, and the situations that come from that, which ultimately leads to your reward of dealing damage to your opponent. I don't enjoy watching combos or counters being broken over and over, which can happen in this game, whether it's because a player was predictable or the other player was lucky. While I like the aspect of it where you always know what your opponent was thinking, and that it becomes more of a player vs player game, I don't enjoy the flow of it. And when it comes to guessing games and reactions, I prefer a stronger focus on more dynamic situations where you need to keep a lot more things in mind than just 4 things.

I didn't say it's not in KI, just that I prefer games with more focus on it. Likewise, Persona 4 Arena and Guilty Gear Xrd have combo breakers, but with a much smaller focus on it than KI.
And sticking to shorter combos isn't the equivalent of Street Fighter, because with other games you're usually guaranteed optimal damage from your punishes. In KI it depends on whether or not your combo gets broken.
When someone whiffs a DP in SFV, they're gonna get crush countered and then you get to do your strongest combo. Heavy reward moves usually yield heavy risk punishes in most fighting games. And those punishes potentially being interrupted by a combo breaker, or me limiting my punish to a small short one to avoid that, isn't a design that interests me. If you make a big mistake, your lifebar is supposed to melt down fast. Thats the flow of the game that gets heavily crippled by the combo breaker system in KI. And even more so because it's not just a simple single limited breaker, but a system and a game in itself that takes up time. Instead, the bigger punishments for risktaking takes place within the combo breaker system. And it gets rather repetetive to look at that so much when that's time spent that can be played in the neutral game instead.

If you don't enjoy the combo breaking system, then that does indeed interupt the flow of the parts of the game you are interested in, because it has potential to happen often in KI. In Guilty Gear, it can happen around once per player every one or two rounds.

Which is what I said as well. But you don't get a guaranteed optimal punish opportunity when your opponent whiffs a high rewarding move, is my point. In KI you can get away with high rewarding moves and potentially get a low punishment for using it incorrectly. Even if you are unpredictable with your punishment combo, the opponent can also guess correctly and get out of it that way. And I don't enjoy that design. Similar to how if you try to open up your opponent for a very long time, and finally succeed, or when you hit someone with a launcher in Tekken, which are usually among the slowest startup moves in the game, I want the reward to match the effort, and not potentially be broken because you have to go through an additional guessing game that can diminish your hard work.
Of course there are interesting aspects of KI's breaking system that I enjoy as well. It can lead to some really interesting mindgames, and I guess that is the tradeoff. I just don't like the frequency of it. When it happens as rarely as it does in say Blaz Blue, and someone predicts and baits the burst, that's hype. But the amount of times I enjoy the breaking system in KI is far outweighed by the amount of times I don't, and wish that time was spent on other aspects of the fight.

That's nice for those who don't want to see too many breaks, but the majority of players do utilize that system. Even if you don't, your opponent can. In terms of gameplay style, there are usually different ways to play most fighting games. Instead of going for the heavy excecution combos for example, you can stick to the easier ones and it may pay off in the long run because you'll end up dropping fewer. Or you can chose to go for a flashy como that's not optimal, just for show. And choices like that are interesting to see as well.
Where did I make a simple decription of KI though?

Exactly!

As you said yourself in your comment - i want the reward to match the effort.

if your opponent does a mistake and you want to punish him

and if you learned a very complex combo and want to use it

it's very annoying your opponent can easily break your combos.

Don't get me wrong.

i think Killer Instinct should have Combo Breakers.

They simply should put limits on that system.

When you can do it countless times 

it causes people to abuse that system.