He's definitely not "risk free", no manager is, but Ranieri is a good appointment for Fulham and is a good fit for how they want to play.
The main issue with him will be his unnecessary tinkering, he needs to find his best 11 and stick with them. If he does that then you'd think they should get out of the relegation places especially with Cairney, Sessegnon, Mitrovic and Schurrle. I'd say they have a better squad than Huddersfield, Cardiff and Brighton.