But let's face it. Gen 2 is just better. It just is.
Please to not be throwing around opinions like they are facts. I've been with Pokémon since Yellow came out, I've played Yellow, Gold, Crystal, Sapphire, FireRed/LeafGreen, Emerald, Pearl, and Platinum, and Crystal was the be-all end-all for me
personally until Platinum came out; but that's just my opinion.
As for whether HG/SS will "replace" Platinum: I think all the people going "OMG YES GEN II PWNED, IT WILL TOTALLY REPLACE PLAT" have proven their own statements wrong. The older games clearly have staying power, for all these people to be so sure that HG/SS is superior to Platinum before we've seen anything but the logos. (Although those ARE some nice logos.) Will HG/SS replace Platinum? Well, did Platinum replace G/S/C in the minds of all these fans? I would say not. And for the people who really love Platinum, I doubt HG/SS will replace it for them.
But in terms of pure special effects and bonus features, sure, of course Nintendo is going to make sure HG/SS is stuffed silly with new tricks and gizmos and subplots and territories for all of us to gleefully run around like the crazy ecstatic Pokémaniacs we are. So in that way, yeah, it'll definitely "replace" Platinum. Nintendo has already promised that HG/SS will have new features that not even Platinum has. (Personally, I'm hoping for the addition of some International Police characters, since the Johto plot is supposed to be happening concurrently with the Sinnoh plot. In FR/LG--I can't say for sure about all the way back in Gen I because I haven't played those games recently--there's even a guy on the S.S. Anne who claims he's with the International Police, on the tail of Team Rocket. So we know they must exist in the Johto/Kanto area, and I think they'd be neat new characters.)
Although I doubt HG/SS will beat out Platinum as my favorite Pokémon game to date (because no matter what new features it has, it's not going to have the entire Team Galactic cast and plotline), I'm definitely going to squee my heart out when I get my hands on SoulSilver. :D Can't wait for it to get here!