It's been relitigated a million times over at this point, but it is very strange to choose an IP and deliberately cut out the one element that gets unanimous praise and legacy; Dr. Facilier and his villain song. Especially since the preexisting bones of Splash Mountain, with the shadow trick effects and ominous build-up as you climb the final hill work legitimately perfect for the song and character in PaTF. But, c'est la vie...
Dig a Little Deeper could work fine, and I'm sure it could pump you up for a big thrill, but it's a big missed opportunity imo.
I'll also say that the finale to Test Track is functionally the same between 1.0 and 2.0, the high speed loop around the building, but I personally believe 1.0 is unfathomably superior simply because of the pacing and tension that the Imagineers set up with the Wall Test gag in the preshow. It's not just a big thrill moment from the high speed, but it's got an extra layer of scare and thrill simply because of the storytelling. With that gag and decor gone now, the High Speed test is almost a little dull. There's no tension, it might as well be an unthemed coaster track. I think Splash will end up better than Test Track 2.0 of course, it will be themed at least. But I do think the drop will probably feel different when it reopens, even if nothing has physically changed.