I'd estimate the guys who came up with Georg's personality never intended for him to return to the series, just like how Ted acts oddly in Suikoden 4.
Yeah probably, they changed the head storyboard person didn't they (after 3)? ...well it was someone important like that, but wouldn't you figure they had some clue as to if they ever had more Suikoden games come out that he would probably be in one, due to the fact that they made his history full of travel....and they already had their names of most of the Suikoden world/Suikoverse (of what we know exists as of now)...like in Suikoden 2 I think Hans mentions he is from Zexen and if you get the best ending (Spoiler
I guess) how you end seeing Jillia and Pilika in Harmonia (Spoiler
end)...and I think there was something about the Grasslands...maybe it had to do with Georg.
And to Runemaster he does look pretty old like 40- mid 50s but S2 did happen after S5 so maybe it was because of the whole S5 thing where (Spoiler
kinda) Farid dies and maybe he just wanted to foget about all of it and not talk about it again (Spoiler