To start with, there's nothing wrong with fuses as long as it's a good installation. People tend to see fuses and immediately panic when there is no reason to do so. But it is true, it will turn off many buyers.
Retrofit kits are not great. They can be fussy to get installed and you always end up with an undersized panel that you can easily outgrow. There are only a couple of good reasons to ever use them. One is if removing the old panel enclosure would create a need for asbestos abatement. The other is to avoid damage to irreplaceable paneling. Avoiding drywall or plaster repair might be another, but those are both easy enough to do. Cables or conductors are easily spliced, it's not a big issue when installing a new panel. If that's your only reason for using one of the kits then I would recommend you reconsider.
Your current fuse box might not even be large enough to install one with enough circuit spaces. Newer codes require much more wire bending and wire channel space than in the past. An older cramped enclosure won't support many circuits.
What would worry me more is the solder and tape connections. I'm not so old that I remember when that was an acceptable method, but I don't think it was OK in 1972. In any case, it's a failure prone method that I would remedy before showing the house to an inspector.
