In the case of Sucker Punch, I think usually it'll be more advantageous to re-equip your weapon, therefore you will ultimately be spending that 1AP to use the skill. Of course, the utility of dropping that offhand for the free knockdown is a powerful recourse, and consequently the battle may tip in your favor.
In general I agree with the idea that fiddling about with weapons shouldn't reset cooldowns (I think this was discussed in another post, just can't find it), but I am not sure about your suggestion of having the skill already in cooldown, especially in the case of Shields Up since it does cost 1AP to equip the shield.
The direct solution with shields, I think, is that Shields Up only restore "shield armor". Basically, say you have a total of 50 armor, 20 from shield. If you get brought down to 0 armor, you can only get 20 of it back.
Sure, that sounds like a huge nerf, but then maybe its AP cost could be reduced to 1AP.
I don't know, I just think there is something weird about the shield skill giving your other armor armor. It's not like fortify or armor of frost. Honestly why is there even a shield-exclusive skill like that? Why isn't there a Leggings Up! or a Chest Plate Up! ?
The weapon-style exclusive skills were added to give more identity to the different weapon options.
Also, raising your shield up to gain a defense boost makes sense as a thing you can do, not so much with a "Chest Plate Up".
The fix here comes down to whether the devs envision players committing to a single weapon style in combat, or whether they want to support swapping them around.
Personally, I feel the benefit/convenience of swapping to the Sucker Punch knockdown, or popping on a Shield to prevent further CC is strong, and something I wouldn't want players to have to worry about abusing. If they *want* this flexibility, then there isn't even an issue here.
The fact that this exists already serves to benefit some builds more than others. It's a lot easier for a Dual-Wielder to pick up an on-the-fly Sucker Punch when needed, even though the ability wasn't intended to be available to their build. Since the unequip is free, and requipping the weapon after is only 1 cost, you're essentially Paying 2 AP for a stun, which isn't a bad deal when you need another. This amounts to a 3AP-cost stun for those that have to first equip a 1-hander and then re-equip their 2-hander.
Shields have a separate issue. You can use one to regain armor, and then unequip it and still retain that armor (up to your max allowed sans-shield). This doesn't make sense and isn't an easy fix.
Shield users also have a big advantage of being able to start a fight with a lot of extra armor, and then swap to a stun after that armor is depleted. They get to double-dip on weapon-granted abilities without even a drawback as they will be scaling off of the "One-Handed" skill the whole time too.
