Yeah i was thinking the same thing about resistance 3 - i loved the 1st but the 2nd really underwhelmed me, and with all this focus on killzone 3 as you say its deffo gonna be overshadowed - Unless of course they manage to pull off something awesome!! (though im still sketpical) 
 
A little worried they are focusing so much on this Melee aspect of it rather than game play itself, though it totally looks like the kind of CQC you see in the metal gear games, and that shit always looked awesome and violent - it does mention in the article that Pachter got hands on with the melee stuff and was not impressed which scared me a little - but then i realised  
 
A) LolMichaelPachter 
and 
B)Kotaku...... 
 
So yeah im gonna take that with a huge pinch of salt, lets hope we get a gameplay trailer soon and something that looks relatively like the promo here in actual execution, as to avoid Killzone 2's ill fated Hype!

 On a side note, is it me or does it look like a Resistance 3 announcement would be kind of silly now with so much emphasis on Killzone 3? "

" @Rhaknar said:

 On a side note, is it me or does it look like a Resistance 3 announcement would be kind of silly now with so much emphasis on Killzone 3? "

No, I agree with you. They'll want to maximese hype and puting KZ3 with R3 may tell people who want both games it's either one or the other. "

There was 10 minutes of gameplay leaked for those who want to see the actual game.  It looks like Killzone 2 with snow and melee attacks.   

Imnsomniac should put R3 on hold - for K3 and to work more on their multiplatform games (which has, I think, a bigger momentum/hype than R3 behind it despite not being announced)