The Tekken throw break system supports reading and reacting as a skill. The entire game of Tekken does; hence why it's so turtly. You only land throws in Tekken when you catch someone with their pants down.
The SC throw system exists to actually break turtles. If I caught you standing, guess what, you done goofed. You then get A SECOND CHANCE to escape damage on top of fucking up, I'd say it's pretty forgiving too. Plus you can use context and position clues to break throws, and reads.
My opinion: A game that is purely made up of read-and-react elements is a bad game. I could go play a sport if that is what I wanted. A good mixture of mental games and some read-and-react elements is better; thus SC's throw system is superior because it actually sets out what it tries to do: Force defensive players to do something.
If you removed throws entirely from Tekken, nothing would change at high level at all. It's just a stupid hurdle you have to get over in order to even begin to play the "real game", just like korean backdash cancelling.
Tekken's throw system is used to break turtles as well, believe it or not. Persistence outweighs resistance. If you keep someone on their toes by making them constantly have to break throws, you can get inside their head pretty quickly. You're able to create openings, and make them antsy. If I just sat there throwing someone for like 20 seconds, they're going to want to start pressing a button in order to get me off them. That's a pretty solid mindgame, at least from where I stand.
Throws are used for level positioning as well, not just dealing damage and mind games. If I have my back to the wall with Dragunov, for example, I'm probably going to mash 2+4, because no matter what, Dragunov's 2+4 throw will cause the opponent and I will switch places, so now their back is to the wall. If they break it, it's my turn don't break it, then I get to use my oki game, which is adjusted for the presence of the wall. Leo is another example of this, as they have a throw that will wallsplat if their back is to the wall, and the opponent does not break it (f,f+1+2). If I remember correctly, players will also switch side on break too.
Throws are never broken 100% of the time in Tekken, even at very high level play in Korea. Just look up some matches on ldmaxi's channel, and you'll see what I mean. Characters have entire setups built around throw game, and some characters like King rely on that (Seriously, all King players do is mids and throws).
At the
highest level of gameplay, there is a small possibility you would not see a difference, but everything beneath that would certainly change. The game wouldn't be as deep, for one, and there would be nothing to break the newfound sanctity provided by blocking. Which, you know, that's a pretty important thing to deal with.
Overall, I would say Tekken's is better, because it rewards practice as well as reading your opponent (Plenty of instances where you can just read your opponent's gameplan and be fine), and just as many uses as SC's system.