Rates options are one of the most complex vanilla desks(if not the most) according to a trader I spoke to on LinkedIn. Cash equity is the least.
Overall, FICC tends to be slightly more quantitative than equities. It's usually what most traders want to work in, as well.
Yeah rates options (i.e. swaptions, caps/floors) is probably the most complex vanilla desk, especially if you do it at a 'top' bank as they tend to trade a few products that most other banks classify under rates exotics as part of the vanilla desk. Also, the current interest rate environment has added even more complexity to how rates options are being priced because essentially pricing models built on the back of Black-Scholes (and other common models) fail with low interest rates, never mind negative ones.
Yes and without an economics degree too. Or without any kind of degree to be honest. I heard somewhere you just turn up on hiring day and the guy with the biggest testicles just gets the job?
Well I agreed with Princepieman but I was just saying that the work itself would be difficult to do unless you're incredibly good at maths. The work is very quanty from what I've heard so you need a very good mathematical ability and these people tend to do degrees like engineering, maths or physics.