Hmm, I do think it's a too easy to swap weapons, but a full action seems harsh, basically you'd miss a whole turn if you want to swap weapons unless you were hasted or could attack with your offhand. I think that might be as per 5e but my sense is that it would make fighting feel even less dynamic than a turn-based system needs to and that matters in a cRPG. Plus it feels a bit unfair to ranged fighters, who would need to lose a turn to swap to a melee weapon to deal with a sudden nearby threat, whereas (unless the whole thrown weapon mechanic were reworked) I think a melee fighter who found they couldn't do damage hand-to-hand wouldn't need to swap weapon set as they could throw a weapon directly from their inventory without equipping it. Though admittedly throwing weapons are a pain so perhaps that balances it out a little.
I'd be okay with something like giving characters the option to define a set number of weapon sets (3 or 4) and giving them the ability to swap freely between them once per turn, but they'd need to use an action if they wanted to swap again or equip a new weapon from the inventory or the ground (which latter I think is the case now). Or swapping between weapon sets costs a bonus action, compared to an action for changing the weapons in a slot, though again you'd need to consider how this impacted balance for melee vs ranged characters.
And I agree you should be able to dip a weapon you don't have equipped ready to throw it, perhaps there should be a "Dip" (bonus) action on the context menu along with the option to throw for any item in your inventory that is dippable? I confess that as I usually play non-STR characters I haven't done a lot of throwing weapons.
Oh, and I very definitely don't think characters should get a +2 to AC from a shield unless they're currently using it.
