Well, I won’t lie, this part of RouterOS is something where I’m sure that I still have a lot to learn.
But AFAIK PCC is just a matcher for connections, I don’t see any indication anywhere that it should care about anything else.
Regarding recursive routes, I already admitted to them being new to me, so there might be some problems I’m not aware of. But in this specific case, I don’t see any reason why it wouldn’t work. I actually did test it. Not exactly with real two ISPs, only in simplified minilab, but if nothing else, it at least isn’t completely broken. 
Recursive routes is not the only way. If you keep netwatch, then with four routes like this:
/ip route
add distance=1 gateway=10.111.0.2 routing-mark=to_ISP1 comment=PROVIDER1
add distance=10 gateway=10.112.0.2 routing-mark=to_ISP1
add distance=1 gateway=10.112.0.2 routing-mark=to_ISP2 comment=PROVIDER2
add distance=10 gateway=10.111.0.2 routing-mark=to_ISP2
raising distance of first one in each table above 10 would make the other one (backup) active.
References to any materials proving that I may be wrong are welcome. Not that it would make me exactly happy, but better than keep being wrong in future. 