Germany is a sure goal for the KHL because of its great market and population. Talks about fans accaption and rivalries come up in every place where the league expands, but Lev Prague has showed larger attandance than any team in Extraliga, while attendance of Sparta and Slavia has grown as well, proving that it's not a problem. I agree that the majority are spectators, not real fans of Lev, but it's a matter of time for new team to gain fans, whereever it is. Team in Germany can do the same way: to have a new team in the KHL and a partner/affiliated team in DEL, so people will be able to choose.
As for German side, having the KHL team can be good for NT to compete on a better level and a team will draw more interest in hockey in general, but it wouldn't solve other problems really, it's a job of a hockey federation.
10k seats arenas that meet the regulations of the KHL team are located Berlin, Hamburg, Hannover, Dusseldorf, Cologne, Mannheim, Munich, Stuttgart, Halle (okay for hockey?) and Dortmund (?). Only 1 team from Germany can join now, because the league cannot take more than 32 teams.
PS The rumors about London and Paris are quite old and there is nothing official about these cities. Actually, there were more rumors about Stavanger (Norway's oil capital), Hannover and even Asia Division. Indeed, as you mentioned, KHL planned to expand to "exotic" hockey places: Milan and Gdansk to build base teams for NTs and will have team in Zagreb next season, but cases of Germany and Denmark, for example, are not that different.