I thought the same, I have a 4 series tractor and the only thing I can't really do with it is run a proper belly mower to mow the lawn with it, everything else from very light duty to heavy almost past its capacity, it can handle well.
A guy down the road that sells round bales lets you load up your own hay if he knows you long enough, I use his 6 series when ever I buy hay off him to load my trailer, that thing with the FEL is handy ish lol, I end up not being able to see the spear when picking up bales and I almost have to stand in the cab to see what's going up there but it's got the auto leveling FEL which helps a lot.
I hop in my 4 series and it's noticeable louder, but maneuvers like a go cart compared, great visibility of the attachment on the FEL.
His is a 6130 I believe, manual with the peddle on the floor for throttle which also makes it handy. Mine is 3 range HST, and for small jobs like moving round bales, it's so much more efficient. But granted it's my tractor, I know my tractor and have had lots more seat time than a big tractor like his, actually his was the first large tractor I have driven.
If visibility was better that 6 series could handle small jobs with no probs, it's turning is tight enough, nothing compared to my 4 series though.
I can see a 1 series getting out grown very fast, a 2 series would work for 85.5% of jobs on a 5 acre mini homestead, 3 series is about what's needed and a 4 series is a bit more than needed but not too big, I have 3 acres but have cattle and feed with round bales. I have never found a task my tractor was "too big" for. Only other thing would be physically fitting in spots like in fence openings or barns ext.
I know I can only park my cabbed tractor in one spot in the barn, it's too tall to fit in any of my lean to's or garage, a non cabbed wouldn't be and issue.