I have had a look at the 2017 and 2018 WHCs to see if there is likely to have been any change in "make up"/politics/allies/influence etc etc (of course the methodology of selection is intended to keep such changes in "balance", at least in terms of "region", as small as possible)
a. 9 haven't changed - Angola, Azerbaij, B Faso, Cuba, Indones, Kuwait, Tunisia, Tanzan, Zimbab,
b. 12 out - Croatia, Finland, Jamaica, Kazakh, Leb, Peru, Phil, Pol, Port, R of Kor, Turk, Viet
c.. 12 in - Australia, Bahrain, Bosnia, Brazil, China, Guatem, Hun, Kyrgyz, Norway, St Kitts, Spain, Uganda
Of the Outs/Ins there are 8 pretty clear straight "paired replacements" with no reason to believe that the "new" country will act/decide/have influence in any different way from the "old" one. I would put these "pairings" as (Old/New)
Croatia/Bosnia, Finland/Norway, Jamaica/St Kitts, Lebanon/Bahrain, Peru/Brazil, Kazakh/Kyrgyz, Port/Spain, Pol/Hun
Which leaves 4 outs and ins which "might" alter the balance of argument/actions
Out - Philippines, R of Kor, Turk, Viet Nam
In - Austral, China, Guatem, Uganda
China is THE new major player who is likely to have significant direct and indirect impact - far above Viet Nam for whom it could be seen as a "Regional Replacement". Who knows what "hidden" impact it might have - particularly regarding the African countries?
Australia adds to the "European" Liberal democracies (sorry Rep of Korea!!)
Turkey was a significant player in the old WHC - but where did it "stand" as between developing and developed, Arab/non arab etc etc?
Uganda increases the straight "African" vote.
"Far East" lost out in terms of pure numbers 3 "out" but only 1 "in" - counter balanced by the size/influence of China of course