It's not really intended to be competitive. It's a one-shtick army, and as such when the one shtick doesn't work, it will fail.
However, I'm not too terribly worried about most of what you posted.
Other hybrid/mech eldar would be a toss-up, depending on how many falcons they take. Would be an interesting cat and mouse game. However, the turn after they get out of their transports, they're toast.
Fire warrior/suit tau don't worry me overmuch as if they deepstrike in, the harlies get them, and otherwise they need LoS. A good balanced tau list would make it hard for my fire prisms to be effective due to railgunning/missile pods though.
Lash of submission also doesn't bother me overmuch, as it needs LoS. Not sure what a chaos bomb is. If it's deepstriking, the prisms get to have a field day with clumped up squads.
Nidzilla doesn't worry me because harlies can handle MCs and they're too slow to get around the cover and a flyrant can be focused on. I've fought lists with wraithlords, and that's basically the same thing. A stealer army with MC support could be a real pain, but fleet of claw is no match for turbo boost.
I'd actually really like to fight a deep strike terminator list with this army. Harlies and autarch could inflict great damage in CC, jetbikes could simply get away, and best of all fire prisms can drop ap 2 templates on nice tightly packed terminator groups. /drool
Honestly, the strongest thing against this army is a basilisk tank with indirect fire. I'm surprised that didn't make the list. Any sort of guess weapon will work well though (but almost no one takes them but guard armies). Drop pod armies would also be decent, though vulnerable to being fire prismed. It's a list with one shtick, but that happens to work well against most opponents. I'd say my list has a pretty good shot at success against most of the army themes posted as kicking its butt. Against armies more vulnerable to its shtick, the results would likely be even better.
What you are relying on is that no-one will get LOS on your units (especially the Harlies) I have found that in reality, an army with multiple units will simply take multiple tests on the Harlies and they will shoot the crap out of them. Other Eldar, Firewarrior/suit Tau, etc... The Whirlwind SM army I sited is actually simular to the Basilisk IG army you mentioned exept it gets Deepstrike and has fast vehicles as well as indirect fire. You missed my Nidzilla point on Dakka, not assault, and Chaos Bombs can normally assault you on turn 2 as well as having Lash Whip(s) to help direct you.
You seriously missed the point aobut Runes of Warding, as it shuts down things like "Fury of hte Ancients", Lash Whips, etc... and I don't find Falcon inpossible to beat down, a smart opponent will shake them as often as possible and simply block their Exit until he is ready to deal with the cargo. I also never mentioned "Fast Necron Armies", as well as others; but again they are another whole story.....
If you like the list, then use it... I was simply stating it was a One Trick Pony, as you said yourself. Sorry to have bothered you.