Michael (KB1PIE):
If you're a"prepper", the two most important aspects of the radio are: 1. Does it work well enough?, 2. Is it easy to simply jump in and use after not using it at all for a while?
The IC-7300 meets both criteria - the FTDX-3000 meets #1 very well but is much less intuitive to use. I have two of the FTDX-3000s (in use at different QTHs) and sometimes use a friend's IC-7300. Both are excellent radios - but quite different.
You sized them up very weil in your first post and are right on regarding FTDX-3000 versatility. It is far more flexible and has better NR than the IC-7300. It's also much harder to use well, until you become very familiar with some of it's more obtuse controls and menus. And if you don't use it for a while - well you'll likely forget some of its quirks and hidden capabilities (like the inverted contour control setting - VERY useful, not at ALL obvious).
Yes, it has a plethora of I.O. that can be VERY useful. I have two of these radios. The RX only port is hooked up to an Icom IC-R75 HF/6M receiver to give dual receive capability which I use to chase SSB contacts while working FT8 digital. This even works cross-band in some cases. I use the 9 MHz IF output to feed an SDRplay digital receiver that can handle a 3rd HF signal if I like, but I usually use it as a super-versatile wideband waterfall display that easily covers all of most bands and can zoom in on a narroe segment in a separate window. The FTDX-3000 microtuner I/O can be used to insert any RX small signal processing you like between the antenna/attenuator bank and receiver front end (TRANSVERTER, anyone?). But I use them for (you guessed it) preselection of frequencies for 20M to 160M using the optional Yaesu microtuner units, and they do their job well (useful in field day like conditions with lots of adjacent transmitters - OR working 160M - relatively- near a commercial AM radio transmitter). The three antenna ports are GREAT! I use one to drive my linear amp and main antenna (Mosley TA-33-MW), one to drive my 60M antenna directly (100W EIRP max, by regulation) and one to drive my 6M antenna. Very, Very handy - minimizes external switching. One of the three RF I/O (antenna) ports can be rigged to be RX only while another is set for TX, with automatic switching, if you'd like to use separate RX (say a Beverage) and TX antennas, which some operators love to do.
The pseudo-IF output of the IC-7300, which about the only accessory signal I/O it offers, is narrowband and of very limited use in IMHO. And of course the IC-7300 lacks all of the other signal I/O I mention for the FTDX-3000. But it DOES have a nice memory card slot that can store a variety of things - including RX audio of extended length.
When travelling, I'd rather bring an IC-7300 - compact and easy to use, though in reality, I travel with an FT-991 - because its also compact and adds all-mode VHF and UHF. But that's a personal preference. My buddy travels with an IC-7300 and EFHW-8010-2K and is a very happy camper.
So - pure capability and versatility - get the FTDX-3000 - very much a "base station" radio.
Easy to use, works well and compact - go for the IC-7300, hands down.
Both are excellent radios. But for the occasional or casual user, I'd recommend the simpler IC-7300, every time.
Have fun and stay safe!
Brian - K6BRN