I think better. Arsenal are going to surprise alot of people this season. Also RVP could be the player of the season this year. He is quality.
About the same. Henry was out for most of the season last year anyways so I don't think it will have as big of impact as a lot of other people do.
I think they'll be better than last season, but that has little to do with selling Henry. They lost both Henry and van Persie for quite a bit of time last season, so, barring more injuries, they should do better just by having Robin back. I don't think they'll be as good in their unbeaten season, but playing so many youngish players in the cups last season can only be a good thing for this one coming up.