I know. I was shocked, too.
It made a big dance of HA! THAT IS EXACTLY WHAT I'VE BEEN SAYING FOR EVER AND EVER! And then I did a little squirmy dance. Now, what am I talking about? Well, I'm talking about the fact that Lex's speech in the barn verbalized a view of the future Clark/Lex relationship that I think is a very true one. To whit, Lex, even when fighting in opposition to Clark (or maybe even especially because of that) is what keeps Clark honest.
Clark's relationship with Lex is what makes him who he is. Lex is a human embodiment of his fallibility, and we see that even more so with the back story that we've gotten in SV. The person Lex becomes -- arch-evil or whatever he happens to be -- is who he is because of Clark, and Clark *knows that*. Clark can see the ways that his behavior molded the man he met into the man he faces as an antagonist. And having an antagonist makes Clark question himself, question everything he's doing and measure up agaisnt what Lex is doing, make sure that he meets his own scrupulous code of honor. And seeing Lex will remind him of a time in which he didn't.
Now, Lex's speech also offers an alternate shippalicious possibility, in which Lex knowingly does all of the above in a less malignant way than one who reads the comics would tend to expect. It offers us a Lex who goes out of his way to preserve the Clark he loves -- who, even far away from Clark with resentment and anger and hurt mixed with all of his affection and love, goes out of his way to keep Clark on the straight and narrow *because that's where Clark needs to be*.
On the subject of Future!Lex, though, I think you have to view SV as a different breed of Superman mythos, becuase honestly I can't see SV's Lex as being this ridiculous heinous megalomaniac who dresses in purple body suits and shoots kryptonite spears at Clark out of little arm-thingies. It would be too tacky for him -- he's more of a corporate evil. Think Wolfram and Hart, or something, and even evil's probably too strong a word. Sure, he does terrible things, but more like, terrible things not for the sake of terrible things, but for the sake of whatever he's after discovering/creating/something like that. And I can't even see profit being his biggest driving force. In fact, future Lex is becoming increasingly problematic for me -- but that's something I'll muddle through later.
Another point I'd like to examine from that barn speech is something I've been saying to Lyra with increasing frequency, which is that Lex Luthor is the hero of SV, no matter how much it purports to be a story about Clark. Lex's interpretation of the story of Numan and Seget seems to me to be AlMiles' interpretation of the Superman mythos. SV really is a love song to Lex Luthor -- it goes out of its way to make *us* see what creates the man in the future and it goes an *extra* mile in showing the Kents' culpability in creating that. No matter what you feel about the characters, there is *absolutely* no way you could watch SV and feel that Lex is an evil man. It's impossible, in my mind, given the *pains* the show has gone to in showing the depths of his vulnerabilty, and the intensity of the back to back betrayals that happen all around him.
To me, it doesn't really matter which Luthor touched the dagger first, because my feeling is that Lionel will always be Clark's true arch-nemesis. In the future, Lex will be his own man, and his actions will be his own, certainly, but SV has shown us that those actions? Are the product of Lionel Luthor. It's Lionel's influence that Clark will be fighting against, far after he's rotted to a mass of really gross hair and bones in his coffin.
Also -- I love the way that Clark refuses to accept the possibility that Lex is his enemy. His lowered eyes, folded hands, clenched jaw, and just broken tone of voice -- god that boy gets to me every time. I'm not a Clark apologist, but I love that boy so *very* very much. Sure, he fucks up, but he's finding himself, and in really trying circumstances, and he really loves Lex, no matter what it is that he's doing. And it's little lines like that one that really hammer it home for me, again and agian.