Well, I did say "almost consider".
Thing is that the best way to avoid
CC is to kill the threatening unit. In your original list 15 warriors doesn't really have the ability to take out an entire 10 man
MEQ unit, even in Rapid Fire range. You could also support with
AB, but then they wouldn't be shooting at possibly more important stuff. You also couldn't really run away, as this was one of your 2 troop units - surviving but losing the objective (and possibly the game) wouldn't help.
In the revised list there are a number of changes which change this tactical situation.
Firstly, a blob of 20 has more firepower, better overwatch chances and more chances of actually causing wounds in
CC (and possibly winning!) Also, the Staff of light is an AP3 shooting weapon, which further tilts in favour of the crons.
Second, you have more troops so tactical withdrawal won't necessarily cost you the game.
Third, the
GA make the 20 man blob very hard to put down with shooting, but also give you the ability to start thinning out multiple units as they approach. If they survive, they also give you the ability to protect the min squad inside for late game objective grabs.
So, with that in mind, weighing up 6 scarabs against another
AB is important.
Scarabs give you unparalleled board control over vehicles. So, if in your meta it is likely someone is going to throw a land raider on the table, then scarabs win this question hands down. They are also an excellent tarpit unit.
Conversely, if you are likely to face flyers, then another
AB may be more useful (plus the
AB can assist in whittling down enemy units).
So, really, this is a case of
ymmv.
Re your comment re immortals and walking, I fully agree that if you are walking without
GA support, immortals are the way to go.
With
GA support (particularly in the case of this list with 2
GA to support 20 walking warriors - if you go with min warriors in
GA.) for me the higher numbers of warriors and lower cost tips the balance in favour of warriors.
GA are designed to synergise with warriors. Might as well maximise that benefit!
I'm sure someone will have different views

this is just my 2c.
edit:for clarity.