When I bought the last three tractors I put power, weight and capability top of my list with ~60hp (net engine output) being the minimum that I would accept. After five years with a BX25D and four years of owning 60hp+ tractors I would never go backwards regardless of property size. An MX6000 is not a big tractor, that's something that you learn after some seat time, and if I only had an acre I'd still want such a tractor.
In retrospect the BX25D wasn't a good fit for me but I learned from the experience and now have two tractors that are just about all I could hope for. I wouldn't do anything different and have zero regrets re my tractor journey or buying tractors with Tier 4 emissions.
Some people are spending $$$ to add a turbo to their 24hp non Tier 4 tractor but they still end up with a small tractor, both in terms of weight and capabilities. For those who want or need a tractor with more power and weight, say 45hp and 4,500lb or more, there are choices, both on the front end and the back end.