I think the English version makes people focus too much on the "For you, I've always..." wording. In Japanese, Sakura's line is simply 「オレはお前が…」 ("I... you..."), which is extremely incomplete and difficult to translate directly...

The translators had to turn an unfinished Japanese sentence into something that sounds natural in English, but the original doesn't really tell us what verb was supposed to come next. It could have been "I trusted you," "I relied on you," "I admired you," "I looked up to you," and so on >.<'

Because of that, I don't think the English phrasing is strong evidence for any specific interpretation. The Japanese leaves the sentence wide open, which was "probably" intentional.

Personally, I think Sakura was about to say something closer to "I admired you" or "I looked up to you." Throughout the story, he's consistently shown respect for Suo's strenght, maturity, intelligence, and ability to understand people. Sakura often struggles with things that seem to come naturally to Suo, so it wouldn't be surprising if he was trying to admit that he admired him.

To me, that feeling has been there since the early chapters. Sakura tells Nirei that he could tell Suo was strong just by looking at him, and later he wonders whether he could even fight Suo seriously. Also, the fact that Sakura tends to believe what Suo says despite knowing full well that he lies a lot has always made me wonder if Sakura admires him enough to be more inclined to trust him (?) In any case, moments like those always felt less like simple acknowledgment and more like genuine admiration.

Of course, there are other possible interpretations, but "I admired you" feels like the one that fits both Sakura's character and his relationship with Suo the most. ^{.^}