Well, I can’t speak for @Alex but I think I can answer your question. 
While you can’t (so far as I know) use a LAN port for WAN you can use the USB port for the 2nd WAN via an inexpensive adapter, as discussed here and elsewhere on the Forum. And, yes, the 20X is significantly different than the Balance 20 in many respects. Personally? I think the 20X is very definitely a “sweet spot” in Peplink’s line-up. (You may not want LTE today but it’ll be there if you change your mind in the future.)
Rick