Would Asari have fared better against a suprise Geth attack:
-A colony of the same size as Eden prime -> since they are all biotics, most likely.
Would they have fared better against seeker swarms:
-A similar sized colony as Horizon not. A bigger one (?) maybe
(Based on the assumption that Collector stasis fields and their seeker swarms have a maximum range and they attacked the main settlement on horizon.
A bigger colony (with more significant sized settlements) would likely be able to start a counter attack on the collector ship from outside this range)
Had humanity been fired upon by the Geth like the Destiny Ascension was, they would've fired back instead of doing nothing. In ME3 fighting the reapers over Earth, the Asari, just like in ME1, failed to fire at anything or at least are not seen firing at anything. The only species we see firing at the reapers are the Turians and humans
yeah, because big ass assari ships are only there to fight in big ass pillow fights...
Snarking aside, if you take a close look to the battle of the citadel (1st part, shortly after sovereign arrives),
you'll see that the Destiny Ascension does actually fire back!
Also, considering the starting events of ME3 I find the statement to pretty bold:
The battle of the citadel is a surprise attack coming from the relay,
the defenders fight back almost immediately, close the citade, and evacuate the council (and also send out distress signals)
Compare that to the reaper arrival in the solar system in ME3:
'Surprise' attack from the relay -> which is several times further away from earth than the citadel portal from the citadel
(Also 'surprise' in quotes because earth isn't even the first planet attacked, Khar'Shan is, but no one seems to be prepared even though the neighbour cluster is already under reaper control...
-> So much for "humans would have ....", the story demands absurd amounts of stupidness from all sides)
We have no info on how the defenders (here most likely the fleets at arcturus and whatever was at pluto) fared, but we know that they did not send any kind of warning, neither scouts nor radio
Edit:
disregard the surprise attack part at the citadel battle, the council was warned. I derped again.