IMHO,
none of those maps should be on an insta server:
Athenosphere - of the lot, this is the "least bad" in insta. -)instaBiB(- record time here is 1:07 I think, but its basically let down by that spam-bait final doorway into the observation lounge, and the fact that the nearest spawn point for the attackers is about halfway back through the map. Which makes things a bit easy for the defenders.
AutoRIP - flat out wank map. Sorry to those who like it, but it is.
Guardia - -)instaBiB(- have actually won this map in 3 of 4 times we've had to play it when other teams chose it. But its way too spammy even on insta. And the spawnpoints make it hard to defend if an attacker kills you as they breach the lavabridge and you spawn way back at the cavern entrance.
GuardiaAL - see above.
HiSpeed - not enough pathing, and too many narrow corridors for defenders to spam. More boots might improve things though.
Lavafort][ - actually not bad on insta, right up until you reach the lift to get to the fort. At which point, if the defenders are even halfway awake, it just turns into another boring spamathon. Unless you play for ]»UC«[ and have cloud's patented slide-0-rama bot to help you get past tricky bits, or luwe's bot to help clear away the defence
Oceanfloor - boring spamathon because you're a sitting duck in the water.
OceanfloorAL - see above.
Submarinebase][ - Another flat out poo map for insta. Poor flow, restricted pathing, corridors too narrow = more mindless spam.
Not saying I could design better maps, but if you look at maps which are good for insta, like Riverbed]|[, you'll note they all flow well, are not cluttered with lifts and shit, have multiple attack paths and are relatively open. Good attackers will do well on these maps, and equally, so will good defenders. The maps listed above all confer an "unfair" advantage on the defenders usually, which makes for boring gameplay.