Yeah, it was about 3/4 the size of GB.
I've never tried Euro Truck Simulator, but I suspect it's probably not my type of game, however, a lot of people love it.
I think whether scale translates to "boring" or "exciting" depends on how you handle it in the game. Is trapsing across the barren waste a major part of the game, or something you can automate and do in the background? Is there pointless filler or does it all have the potential to be a place of interest if you stop and start to build?
For a Europe map for stronghold PW mod for or more realistically, for M:Epic, I think huge scale could work really well for this type of game, but it does need an approachable auto-travel system - like strategus - you don't generally sit there and watch your guy travel all the way across the map. In M:Epic, this could be an alt that you occasionally check up on and set new waypoints, while most of the time you're playing with your other characters.