I don't think Arsenal have done as well as people are suggesting. Pepe could be good but they've lost the creative influence of Ramsey and didn't replace it. Iwobi another who created a lot for them and they're left with Ozil who has been hit or miss at best for a while and the loanee from Real Madrid. Tierney coming from Scotland to a proper league will be a big step up who might need time to adjust and David Luiz has never been a solid defender and he's getting on in age.
Man United I think have got quite a lot weaker. Massively overpaid for Bissaka and Maguire. Lost Lukaku and signed a teenage winger. Where will their goals come from now?
City I think have done the best business. Two top players which are big upgrades for their positions.
Ramsey hardly played last season for them, was injured at start of season and then again since January, don't think he is big loss for Emery. Ceballos seemed brilliant when i watched him at young Euros for Spain, i think he'l come good for them. Iwobi completely lack end product, every time i watched him play he would panic when found himself in good situation, he always seemed very average, good with a ball in feet but never do anything when found himself in good position. For me, their attacking trio look brilliant, their midfield with Ceballos and Torreira solid, but yeah defense is still not good, though Bellerin and Tierney if they stay fit (big if) gonna add a lot toward their attacking play, Emery like attacking fullbacks.