That's not how it has been as far as I remember.

Not even Citadel?

Brand new mechs were never a available easily upon release afaik, apart from paying. As time goes on it will be available via different means, like maybe the top prize of a playoff event or ECRs. Right now the only f2p way to get it is through the one token in onslaught and some good luck :-).

Another killbot for noobs. Thank you.

Played against a bot in hangar showdown named Tails

I think they did do a-coins crate rush after the initial paid only crate rush with the free token for each blizzfrost and citadel

The tailsting ecr is for the mech RELEASE, which are mostly paid-only, though you can often get a free token or two.

Then later tailsting or others will potentially appear later in acoin-ecrs 

Bro we free to plays are getting cooked by these new updates wth plarium??

Is 

Even if they did, I think the key phrase here is "after the initial paid only crate rush". On release
there is no immediate acoins ECR or for that matter any playoff-based
reward. The paid-only crate rush is what is currently ongoing. IMO any
acoins based ECR will not be in the very near future. 

For Citadel I don't think there has been a guaranteed-reward, acoins-based ECR yet. If there had been I would have it :-).