I played the Famicom and SFC games and I liked them.
The FC game you need patience though, the AI takes forever to make its turns even with fastforward, and once there are enough units on the screen moving stuff around is quite laggy.
With that said I enjoyed them. A lot of rules are different compared to the GBA ones, for instance you can only use your base to build units, factories you capture in the field are only used for refilling, you can't land units on mountains/forest tiles and it takes two turns to load a unit into a transport vehicule and then move that vehicule; etc but there are also unit types that don't exist in the GBA ones. The SFC game also has (optional) unit exp/level up system.
Also, difficulty is actually better in the FC and SFC games than in Advance Wars (1). Perhaps even AW2. The AI is really bad in AW1. On top of this, there are two difficulty settings in the FC game and in the SFC game generals are more or less good which also works as difficulty settings.
In both games you need to beat the campaign twice, once on each side, to see all the content because the last map(s) are unique to each side. The final two maps in the SFC game were hell, harder than anything else I played in AW1/2/DS
Just give them a try and see if they hook you or not.