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Well, I don't think that matters much. Whether they are playing at the Etihad Stadium doesn't really matter, especially considering the last match Arsenal had with Manchester City at City's home, which resulted in a two against five defeat that Arsenal inflicted upon Manchester City. So even though they were playing at City's home, Arsenal was able to beat them in their last fixture togetherr, as a competition.
Arsenal managed to win their last two matches against Manchester City, including their penalty shootout win in the Association Community Shield match with a penalty score of 1-4. But during regular time, Manchester City and Arsenal only drew 1-1 and what you say about the big score is basically not true.
Home matches are very influential for Manchester City and you should take that as an important thing that you should not miss when making analysis. Manchester City have won 4 of their 5 home games against Arsenal, so the home game should be the benchmark for who has the greatest potential to win it. Here Manchester City is the favorite, so I don't think it will be easy for Arsenal to win this match.