As far as features and bands - I really have no need for the radio to do anything other than HF. I have VHF/UHF radios, so I'd rather get something that is best at HF and down rather than OK all around.
One advantage of having VHF/UHF as additional bands on your HR radio (with most anyway) is that they will do SSB on those bands as well. Most typical VHF/UHF radios will only do FM with some adding a digital mode like Fusion or DStar
Features - the biggest thing I would say is, I am very much used to having a waterfall display since I do a lot with SDRs. From talking to a really helpful member here who messaged me, I found that I can have that even on radios without one built-in - but I think the IC7300 is looking really nice since it has that plus a lot more.
This is mostly true, but your radio will need to be able to pass the data on to your computer. The waterfall display requires the radio to pass the signal patterns for not only the frequency tuned in, but a range on both sides for the display to function. Many will do this out of the box, but check if it's a "must have" or a "high want". Even some older tube type radios can be made to do this if they have a "Pan Adapter" installed that taps into the IF signal.
As far as digital stuff - I don't really think I need all that much fancy stuff - after all, I can just hook it up to a computer and use an application for that, right?
Yes, most digital modes can be done on nearly any HF radio using an sound card interface such as the RIGblaster line. You'll also need some type of rig control interface for them to work like most folks expect. Often this is USB or RS232 (aka serial port) and your radio will need to have the required connection for your sound card interface to plug into. Even some very old radios have or can be modified to have this type of interface. My mid-80s Kenwood has a replacement card available to add this feature. The newer the radio, the more control this connection will generally provide, but often you really don't need much for the typical digital mode software to work.