I bite that same bullet.... no regrets..... I like it and enjoy it, and intend on hitting the market with it too...lol I have not plowed anything in days !!!! woo hoo.
Not sure about the 4x4 Combine. That is almost equal to the 5x5 when you consider how many fields are not wide open, and require working in various size locations.
But perhaps the simple 2x2 Combine which can be used at the farms of those who are a bit unwilling to "do the work" or "pay the price" of advancement which older players have dealt with. If you have a 3x3 or 4x4, you can get the 2x2 Combine "cheaper" than what a 2x2 would pay. IHMO there needs to be a definitive difference between high levels and low, $FC and coin etc.
I have a cousin who plays.... I am even considering the combine as a gift... because it would be fun to give it.
.