I saw Let The Right One In the full two years before its US version came out on cable, so there was sufficient time for me to have a slightly dulled recollection. There was definitely concern before watching Let Me In that it would be either a sloppy horror film or more of a Twilight type love story than I could stomach. So I definitely watched with a skeptic's eye.
A few days later I watched the original again. That's when I noticed the discrepancy. I don't think it was completely omitted in the remake, just delivered to the viewer differently and not as powerfully.
The original was probably predestined to be better if only because it is foreign and that dark Scandinavian familiar-but-strange feel really fuels the already ethereal and Grimm fairy tale tone of the film. I thought it was pretty smart of Reeves to set his film back 30 years. It was a good mechanism to grab at that same surreal familiarity.
Anyway, if I were rating them with stars I'd say LTROI is a 4 and LMI is a 3 (maybe a 3.5, I should give it a second viewing). The acting and directing is strong in both, but the little differences (foreign feel, pool scene, 'the reveal') edge the original a bit beyond the US version.
Along those lines, have you seen both versions (or either version) of Insomnia? I prefer the original there as well, but it's hard to argue against a Christopher Nolan and Al Pacino collaboration!