many people don't realize how vulnerable the At-Ats are to the SnowSpeeders..
a single snow speeder can easily take out both At-Ats if they are undefended..
the At-Ats are strong only if they have a good support team..
most people will just jump in the snow speeder and try and gun the At-Ats down with the main guns.. what they don't realize is they are not really doing any damage.
also 3 Rebels with rocket launchers can easily take down an AtAt before it reaches the first marker....
as a rule of thumb.. never judge a teams strength or weakness based off of a public game... 90% of the tiem little or no team work is present in those situations..