Battlebond is out and there are only two cards in the set that specifically reference commander:

Will Kenrith
Rowan Kenrith

I don't think this pair is very good, but, that's not going to stop me from wanting to build them. The thing I'm having the most difficulty squaring away is protecting them from attacking creatures, while they have fairly punishing mana costs (and while the partner aspect makes that better, it's not great).

Many of the traditional options (like Propaganda) will be non-starters because they're planeswalkers.

So, aside from board wipes/mass bounce, how would you protect these dorks, especially keeping in mind that tapping out for them will probably be necessary from time to time?

Also, how can we punish people for attacking us (and let's say they have to, because of Rowan's +2)?

Honestly, it seems that the most coherent strategy for them is simply UR Superfriends. It seems they simultaneously want fat-bottomed creatures, permanents with activated abilities, and spellslinging all in the same deck. In any other deck type, that's a lot of dissonant themes to add together. Adding more planeswalkers will make each fat butt (and proliferate effect, and anything else you'd add to the deck to empower walkers) that much more useful, and you can then you can get a standard UR draw/removal package. Adding more PW's is also a good thing for the two of them as it gives your opponents extra targets, making it more likely that one of them will escape each combat unscathed.

Also, whenever possible activate Rowan's ult before Will's.

I agree generic control might be the way to go. Still trying to piece together how I plan on winning, etc.

Also, definitely Ult Rowan before Will

All kinds of way to discourage attacks.

War Tax to keep their creatures attacking someone other than you
War's Toll to keep them off mana when you are taking your turns
Maze of Ith of course
My boy Kazuul, Tyrant of the Cliffs
Aetherize if they come at your wonder twins
Sleep is good too, one of my favorite blue cards
Dismiss into Dream fights aura and equipment decks pretty good, also removal with your blue CMDR

You could also go a STAX route and use Meekstone and Embargo effects.