TL;DR: I would invest in slowbro
I personally would wait until the gym rework happens to evolve it. Currently,the general consensus seems to be to obtain Pokémon with the same type of fast and charge attacks, or at least both stab.
If I'm not mistaken, slowbro and slowking have the same stats, the only difference is slowbro's access to IB & WP whereas slowking had access to Bliz & FB.
In my opinion, IB > Bliz, if you want to use them for defensive purposes, and both are about equivalent at attacking (blizzard may have a slightly higher dps).
Therefore, it depends on what you desire. Me personally, I think C/IB is solid on defense, and would rather obtain either a WG/P on either, a C/FB on slowking, or a C/WP on slowbro. Just me personally.
Anybody that has read a number of my responses recently will notice that I tend to hypothesize about PvP and which Pokémon will be helpful at creating a squad. I think there are many Pokémon that will suit well after a potential gym rework where I ASSUME one of the major differences will be a removal of cp as a determining factor for gym placement, thereby making either of these two slowpokes worthy.
In regards to PvP, I am ASSUMING that Pokémon with:
- fast and charge moves with short durations
- charge moves that require a minimal amount of energy, e.g., multi-bar charge moves
- staggered (different) types of fast and charge moves
..will succeed in PvP. Again I reiterate that these are assumptions.
With that being said, IF these assumptions of either PvP or the gym rework hold true:
- WG + anything on slowbro will be successful in PvP, as slowbro gets access to two 3-bar charge moves
- Either slowbro or slowking will do well on defense (I would roll for slowbro and hope to get C + WP or IB {which you already have})
In summary, both are good options, but I would roll on another slowbro and hope for the best. If you want a different slowking (for defensive purposes) then I can see that as well and would evolve into Slowking. Either way, I hope you get what you want ^^
