I'm seriously starting to believe the rumours about them somehow having no money to spend. Ridiculous that keeping Sanchez constitutes a success day and close to the window for them, they still need improvement outside of that!
If Chelsea/Barca aren't in for him, then £45m on Mahrez would probably be a sound investment. Would suit their style, has proven his ability in the PL and although he's started a bit shit, I'd expect his level of play to pick up once he moves away from Leicester and is in it a happier frame of mind.
Drop another £40m on a good CB (Manolas? De Vrij?) and they'd still only have spent about £60m net this summer, surely they can afford to do that?
4-2-3-1 with Ozil, Sanchez (if they can convince him to put in effort), Mahrez and Lacazette should see them score plenty of goals and be more solid defensively than they are, wrap up Ozil's new deal and suddenly things are looking up a bit.
Of course, this is all FM18 fantasy stuff at the moment and none of that is likely to happen.