This is giluy Shechina, the revelation of the Divine Presence. And the prooftext is Devarim 4:34:
|לד אוֹ הֲנִסָּה אֱלֹהִים, לָבוֹא לָקַחַת לוֹ גוֹי מִקֶּרֶב גּוֹי, בְּמַסֹּת בְּאֹתֹת וּבְמוֹפְתִים וּבְמִלְחָמָה וּבְיָד חֲזָקָה וּבִזְרוֹעַ נְטוּיָה, וּבְמוֹרָאִים גְּדֹלִים: כְּכֹל אֲשֶׁר-עָשָׂה לָכֶם ה אֱלֹהֵיכֶם, בְּמִצְרַיִם--לְעֵינֶיךָ.||34 Or hath God assayed to go and take Him a nation from the midst of another nation, by trials, by signs, and by wonders, and by war, and by a mighty hand, and by an outstretched arm, and by great terrors, according to all that the LORD your God did for you in Egypt before thine eyes?|
There are two possible aspects of this pasuk which might serve as prooftext. It might be וּבְמוֹרָאִים גְּדֹלִים, 'with great terrors'. In which case, it is the shorter Arami Oved Avi text pointing the the more expansive text elsewhere in Chumash. But that would not show that this was giluy Shechina any more than the pasuk local to Arami Oved Avi, which has all the features of otot, mofetim, and zeroa netuya.
Rather, I think it is the very last word of the pasuk, לְעֵינֶיךָ, "to your eyes". Thus, it was something you could see, and so it was a revelation of the Divine Presence. And this לְעֵינֶיךָ is modifying the last of the list, the מוֹרָאִים גְּדֹלִים.
I've pointed out many times in the past that Chazal have darshened what appears in the Samaritan text, rather than out Masoretic text. Indeed, earlier in the Haggadah (and Sifrei), we saw the Biblical text cited as גדול ועצום ורב, though that was more innocuous. I believe that this is another such instance. Come and see what appears in the Samaritan text, in Vetus Testamentum:
The Samaritan text appears to the left, where it differs from the Masoretic text on the right. They have ובמראה גדול. It then seems that they take the root as ראה, seeing, rather than ירא, fearing. And thus, the derasha.
With the focus on gilui Shechina, I think that we have not yet lost focus on Ani velo malach.