Nothing is impossible for 90 minutes. Arsenal have a higher chance of winning because of the quality of their players, but Crystal Palace can also win if they are good at taking advantage of every opportunity that is created in attack.
Arsenal is stronger and they should win the opening match of this season. After a good transfer season and good friendly matches, a win in first match in Premier League will be good and motivate their team to aim at higher position in this season. They don't want to finish beyond top 4 in this season.
Gabriel Jesus is indeed quite good as a striker for Arsenal, he may have good finishing stats as a striker, but believe me Arsenal can still lose if there are many chances and well taken advantage of by Crystal Palace players. Arsenal have the potential to win today for the start of the season, I'll be looking forward to that.
He can play as a striker and in other positions in attacking system of Arsenal. Through his experience with Pep and Manchester City, he will not have troubles to understand the tactics of Arteta and I believe he will be able to play well in Arsenal. He won't need too many time to be familiar with Arsenal and Arteta. His performance in friendly matches confirm my thinking too.
Last season Gunners had a missing piece to their attack but this season seems like we got everything we need. Maybe a slight of investment in defence could have been good but anyway I think it's still enough and I can see we have better chance making into top 4 (atleast I hope so).
I don't think they lost a position in top 4 to Tottenham because their attacking system is bad. In late phase of last season, their young players could not control themselves and could not play well under pressure of themselves and from Tottenham. It is the first season Arsenal was very close to top 4 in last 5 seasons or more. Pressure is big and they failed to protect the fourth position in last 2 match days. They lost it to Tottenham in last 2 match days and it's too late to do anything.