Some people are calling for Emery to go already, but that's not the solution right now. Especially after a mere 6 months.
There's a lot of your fans that thought that it was just a matter of getting in a better coach to significantly improve results. It was never that easy. There's a lack of real top notch players in key positions.
We had a lot of iffy players at the club when MP arrived. However up the spine of the team we had Hugo, Jan Vertonghen, Mousa Dembele, Christian Eriksen and Harry Kane. That's a great start and they'd all been at the club for a while.. Chuck in Kyle Walker and Danny Rose and you've got 80% of a very decent back line with some very decent players to play in front of them.
Arsenal's rear guard has ageing players who need moving on - Cech, Koscielny, Monreal, Lichsteiner and some who just aren't good enough - Kolasinac, Mustafi, Sokratis and Leno. Bellerin (he's got real pace but he's not great defensively) and Holding are the only ones that have a future at a top side.
In midfield, Elneny and Xhaka just aren't good enough. Torreira is. Guendouzi's promising but very inexperienced. Not sure about Iwobi. Losing Ramsay now is bad timing but he's not worth the cost of keeping him.
Up front you've got 4 players that, collectively, are said to be costing nearly £1m a week in wages. The problem is that you can't really play one of them at all and probably only function as a proper unit with 2 of the others on the pitch at the same time.
That's a lot of work to sort out. MP had managed in England at Southampton before Spurs. Emery's never managed here and he's had a similar experience to Pep. Strong start followed by some bad results and a significant drop off. Pep had his reputation, vast sums of money and CL football to aid the 'transformation'. Emery's got a much, much bigger job on his hands. History says it'll be the next manager after him that starts to get it right but he seems like a nice bloke.