yeah I saw in one of Erik's live streams the new upgrade tree, and I saw hammer with 2 size upgrades... was blurry so I couldn't read the size gain percentage :)
Final version they won't be able to be kicked, and colliding hammers will probably knock back with a "stun" for both parties. Or at the very least both not landing either attack.
(Commentatron) You'll not be replaced, we'll only remove half of your internal systems and replace them by a more advanced one... you'll be the same, but you'll be a better version, all of your clones have it!