They've been directional as long as I remember. If they were to diplex with KLSD permanently, that would mean a switch to non-directional operation. Sure, that'd make things simpler, but wouldn't being directional have advantages so that they could focus the signal where they want it, while minimizing signal toward other stations that need to be protected?
And if they went directional, what stations could they maybe diplex with? I'm thinking...
910/KECR and 1170/KCBQ - the 2nd of those stations is a bit close in frequency, but if they could use that site, they could focus all their signal west/southwest. There isn't much population density, relatively speaking, east of the site, so they could effectively protect KWKH. Also this site has 7 towers.
760 KFMB - only 3 towers (instead of the 6 that KSDO currently has), but maybe would be an alternative to the KECR/KCBQ site? And it's not very far from their current site.
600 KOGO - only 2 towers, and in the middle of San Diego, so some communities to the east like Lemon Grove, La Mesa, El Cajon, Santee, etc. might have to have a reduced signal. (Personally, I wouldn't mind, being a couple miles south of El Cajon, so I can receive 1110 KDIS better, but I'm not the one calling the shots.)
1210 KPRZ - not sure if this is too far north, but would it possibly work? In this case, they'd beam the signal south, protecting CKWX. They could also maybe have a notch to the east to also protect KWKH. It might weaken the signal over I think Rancho Bernardo or north Poway, but could the side of the lobe, heading south, still hit Lakeside, Santee, El Cajon, etc?