In most games these flares are useless to the player because AI opponents don't use real vision... but since MWO will be entirely player-vs-player, then a blinding flare weapn would be very, very useful; especially in a game dominated by "Information Warfare" where direct line-of-sight engagements depend on "sight."
This is how I see it: a scout fires a flare-type weapon at an opponent, and as the flare approaches in proximity to the opponent's cockpit their vision becomes increasingly bleached-white and slowly returns to normal, leaving behind a very slowly fading green-and-red spot (you know, just like a spot that gets burned into your vision after looking at a lightbulb or something bright) that persists exactly where that flare was in relation to your visual field. If the flare comes at you from the front left, then the greenish/red spot would be on the left side of your pilot's field of view, and it will remain there, on the left side of your monitor, even if the pilot looks around in their cockpit because the spot is burned into your pilot's eyes so it should remain right there until it's finally faded away.
Edit: Some have said that Mech cockpits have self-tinting glass that would mitigate this effect during daytime engagements. It still would be effective at night to completely bleach-out Light Amplification systems. Also, I think the self-dimming cockpit glass would become too dark to see through at night whilst a flare is traveling in your direction.
Edited by Prosperity Park, 10 January 2012 - 12:03 PM.