are you fucking trolling me?
First of all there is no preview of Half Life 2 Ep 3 or Half-Life 3
Secondly Half-Life 3 (or Ep3) is arguably the most anticipated PC game ever (stupid Sims don't count) so if Valve would screw it up I can guarantee you that THE INTERNET WILL BE FUCKING MAD and on a scale 100 times bigger than with ME3
But we are talking about Valve here, maker of the best game ever and run by Gabe Newell aka. Gaben the biggest legend in the gaming industry (also in physical size ~~). So screwing up their Half-Life franchise like scrub BioWare is very unlikely.