The secret of using scouts as a counter to LRMs is now very widely known and it along with the increased strength of LFs has transformed the game into one of Scout/LF spam.
I strongly disagree with this.
First of all, Scouts only counter one thing, and that's LRFs. LF's counter 4 things, Flaks and 3 Cruisers but even still, with simple LF + Scout spam, you will be extremely weak against capital ships.
LRFs counter not only LFs, but also capital ships, and to a MUCH higher degree than LFs could even dream of. Do you have any idea how long it takes for even mass LFs to take out a cap ship? I won't even bring up mass Scout's against caps because it's just pathetic, it takes forever.
The problem with building only a LF+Scout fleet is that you then become very weak against cap ships. If your opponent gets a few Carrier Caps and some LRFs, he will be able to kill your caps faster than you can even escape with bombers. Sure, you may kill some of his LRFs too but what's more important, taking out caps or killing LRFs?
As has been said many times before, Scouts scale very poorly into late game. They are easily countered by the same things LRFs are countered by, including other Scouts, and everything else you mentioned. However, Scout spam is also countered by Flak, something that LRFs don't even have to worry about.
I agree with everyone here that Advent Scouts need a nerf, but holy crap, with how broken Illuminators are right now - it doesn't even matter. I would much rather take Illuminator spam over Scout spam anyday with the DPS these things can put out now.