Just compare it to MA Ryleh, the insanity hits most of the time your own units. Insanity hits your own commanders, while ilithids are a bit resistent they get hit too. Its just a big hassle to play. Each round giving insane commanders of previous turns the same old orders back.
Now with MA Ryleh we do not have that. Also no need to take growth scales. Better control over upkeep. Just 1 gold per 15 unit? Its still too much. Cause you will have a lot of units with dom10. Play with lower dominion and there won't be that many. You will have a problem to build expensive castles too.
Oh, i am sure you can win with them, but better compare it to MA Ryleh and how much hassle it is to control them in LE compared to MA.
This is not a thread how to play LE Ryleh, btw. I am against upkeep for freespawns coming in such huge numbers in a high dominion, resulting in no control over your finances. Again cannot imagine how thematically those highly insane hybrids would use gold anyways, cause then soulless and longdead should be paid too.