as i said, his system is more than just adding a centre back. if you take a look at the rest of his quote:
"But I have to sell my idea, if I change all the time it will be even worse. But I understand they have a lot of difficulties because they spend two years playing one way and now playing another, with a lot of losses, is really tough on them and you can feel it during the games. Even when we try to score, was more from them than the organisation. You have to feel it. I have to sell my idea, I cannot find another one."
you can clearly see he is trying to implement a new way of playing.
in fact, it's such a ridiculous point you're trying to make, suggesting that Amorim's system is more of less the same as ETH's - there must be 50 threads on this forum discussing his style and system. i'm happy to talk you through the stylistic differences, but I also don't believe what you're saying, I think you’re just backing yourself into a corner to try and justify your point. i'm assuming you must have seen the odd Sporting game for starters.
of course we shouldn't be played off the park by Southampton, but as i've already said, it's a combination of a) the players still learning his system and, more concerning b) some of our players are simply incapable of playing the way he wants - largely because we have a whole lot of dross in our squad. it's not difficult to see this will have a downturn on results.