The significance of this line does not lie in the supposition that Razer, like Hal and Kilowog, is surprised and impressed by Aya’s capability. Note that when Aya first informs the crew that she alone can and will complete this task, Razer smiles and nods in agreement. He has no reason to doubt her capabilities. Throughout the series, Razer has often paired up with Aya on missions, and she has time and again demonstrated that she is not only able, but necessary. While Hal and Kilowog don’t disrespect Aya or think her incompetent, they are still stuck thinking of her as the rookie. For them, Aya’s perseverance and her strength in this endeavor come as a surprise. She is proving herself to Hal and to Kilowog, but she has no need to prove herself to Razer.
The meaning behind this line—and it is a line that the show itself stresses, with the camera panning to focus and close in on him as his face changes, slowly, in realization and acceptance—instead draws on the great and largely unspoken drama of Ilana’s death and Aya’s (unknowing) decision to pattern her mechanical form after Ilana. Razer does not recognize Aya’s mechanical form—her face—as Ilana until it is explicitly pointed out to him by Queen Aga’po, and his horror and anger is immediate and profound. But he does not bring this up again; he does not castigate Aya. There is a sort of chill between them in the next episode, marked less by any deliberate snubbing or cruelty on Razer’s end than by a sort of silence. Where they talked often and casually in previous episodes and frequently communicated through body language (looks, touches, etc.), instead there is little of them. But it is a thin and fleeting silence. Razer does not lash out at Aya, but recognizes her skill and her rescue of him. In the episode after, when Aya is incapacitated by the yellow ore, Razer is quick to notice and to catch her; he spends the rest of the episode positioned protectively about her, whether physically or emotionally (such as when Byth Rok teases Aya about marriage). Given this, it is easy to speculate that the little distance between them is because Razer, ever given to guilt, is ashamed that he did not himself notice Aya’s physical resemblance to Ilana, and, considering also the line from “Invasion” in question, because he is also questioning the reason for his attraction to and feelings for Aya. Does he care for her because unconsciously he was responding to her physical similarity to Ilana? If not, can he even look, now, at Aya and see her not as Ilana, but as Aya?
So when Aya throws herself into danger to break into the fortified Lighthouse, when the others realize that Aya isn’t a rookie but as necessary and valued a crew member as any of them, Razer realizes this instead: Aya is not Ilana. There is more to Aya than meets the eye; e.g., Aya is more than Ilana’s form given new life. His feelings for Aya did not arise out of his feelings for Ilana. The groundwork for Razer and Aya’s relationship begins well before Aya even takes on a physical form; they converse repeatedly when she is only, to his perspective, a disembodied voice from a computer. She is Aya before she takes Ilana’s body as a blueprint for her own. If he loves Aya, and he does love Aya, then he loves her for Aya.
(I’m of the opinion that confirmation from the show’s staff that it was Razer’s love for Aya that enables the Star Sapphires to transport him to her location isn’t necessary; it’s quite obvious, textually, that this is the case within the show. Nevertheless, as it appears there is still debate as to whether or not it was Razer’s love for Ilana that enabled such, well, here you go.)