It should also be noted that this problem didn't really exist in A16. In A16, I mined, and I got better at mining, I built, and I got better with construction tools, etc. My skills progressed naturally, and doing things made you better at those things. Was it grindy? I guess, but it was intuitive.
Notably, If my friend LIKES building and mining, and chooses to do those things, while i kill zombies - suddenly i'm better at the things HE wants and chooses to do. Killing zombies makes me better at other stuff then the people that choose to do those other things. Since XP is now the ONLY progression mechanic, something that gives 20x more xp than any other activity makes me 20x better at doing EVERY activity.
Kill zombies to learn how to swing a pickaxe better?
Kill zombies to learn how to boil an egg?
Kill zombies to learn how to heal my injuries?
Kill zombies to learn how to smelt steel?
Kill zombies to learn how to haggle for better prices?
Kill zombies to learn how to deal with hot and cold?
Kill zombies to learn how to more efficiently dismantle a car?
Look. I LIKE being able to advance my noncombat skills with combat...it means that unlike in A16, I don't have to work so hard on upgrading blocks to get construction tools to a certain threshhold just to be able to make iron weapons...I can just kill some zombies and spend the XP.
But adding this feature for the combat people left the people who PREFER noncombat (They still do it...no one who has zombies on in this game DOESN'T fight at all) WAY WAY behind.
In A16, I had to fight to be better at fighting, craft to be better at crafting, mine to be better at mining, loot to be better at looting.
In A17,
I can fight to be better at fighting, and fight to be better at not-fighting
My friend can not-fight to make no progress at fighting, and not-fight to make no progress at not-fighting