It will work for sure, IP passthough is the way to go if you want your ASUS to be in ''charge'' of your network. It will basically forwards everything to a specific port, and the web interface of the Cradlepoint will guide you to this in 2-3 steps. I never used 4G LTE as a main internet connection at my home or business because where I live, the carriers offers small data plans with not a lot of bandwidth or if they do, its 5x more expensive.
IE : 6 GB of data and a 8 Mbps is about 75$ a month.
So it is more of a backup solution in my case. Some business grade routers that I buy come with a USB port for a backup 3g-4g connection. I have configured specific QoS rules on the backup interface because I need it to conserve the bandwidth and only serve mission critical applications.
I guess it depends on your needs and plan you picked up, some data plans in urban zones are way cheaper and faster. Does it actually suit your needs ? What are you trying to achieve with the replacement of your unit ? More speed, more reliability, more manageability, more devices connected ? The Asus router is a great unit, for some people its overpriced, for others its just a consumer grade router.
A common problem that I see with constant usage of a "cheap" USB stick for 4G, is the heat building up.