I love the tallos, they normal provide longer range AI, great anti FMC and can destroy whole squads of Marines, and tanks that get close. Of course they can be wiped by termies etc, I find they are are more durable then ravagers. But you are probably right that 3 more ravagers would be more powerful and more fitting with our glass hammer theme as long as your opponent doesn't have an answer for it
Although the khymeria I haven't had much success with, they are almost the same points per model as the razorwing (although 5 per beast master) they only have 1w and fewer attacks with no rending. But the big kicker for me is the point effectiveness with the Baron, the stealth bonus and ignoring difficult terrain means the the birds unit will pretty much have a 4 plus cover save or better most the time, so I gain very litter from adding khymeria flocks but pay a ton of points