The issue with Griezmann for me is not whether he is good enough but it is one of competition. He had the opportunity to come this year, and hasn't, most people are saying this is because of the Atleti ban, I am not so sure. If that was all that was stopping us why don't we have an agreement for him to come in January or next year (anyone who thinks we would be hiding this for some reason is deluded). I suspect that he decided not to come initially because of the ban, but he has then seen how things have developed at PSG and Barca.
I can't see him leaving in January, as that would leave Atleti in a bad position, so it will be next year, and that means we will face competition from Barca, Real, PSG, Bayern, City, etc especially if the price is 100m. PSG could offer huge wages to Griezmann outside our range, Barca are Barca and I am sure he would love to play with Messi, Suarez and Dembele, the others also have attractions and then we have us.
Griezmann if he really does love Atleti may also agree to sign a new contract so that Atleti get an even bigger sum of money, after all why wouldn't he? He would get a bigger pay packet as a reward, plus he helps Atleti in the transfer market. I can't see us being the winner in either a 100m clause fight (due to options), or in a straight out best offer fight (City and PSG will blow us away)