So, it seems to me that there only are two instances people are playing once they hit 85 to 90: Odin and Abbey. It would be nice to get at least one more viable alternative out there. I'm sure there are on paper, but for whatever reason, people apparently do not agree with it since 99% of the times I see LFP in recruit chat for those at level 80-85 or above, it is either just Odin or Abbey.
Economists call this 'revealed preference'. This clearly means there are problems in the other alternatives. IMHO, there should ideally be 5 or more places, but one can at least start working on just a third alternative to begin with.
Secondly, maybe improve solo levelling spots by increasing mob counts for certain monsters which give good exp(like high orc, alarms etc) which would help solo levellers and make people less dependent upon grouping up.
Third, perhaps introduce more quest for those at level 90 or above, particularly reborn.
Just my two cents.