I think the X7 series can handle the little loaders that would fit it. After all they can only hold and lift so much. The one thing that might concern me is the front axle. Not sure it's made to take the 900 or so pounds (loader and load). But if just using for mulch and some light work. It's far superior to a wheel barrow and less impactful to the lawn than a bigger tractor.
As for counterweight, you just have to be set up to easily add/remove weights, like with suitcase weights and a weight bracket. I have about 500 lbs hanging on the back of mine. Can easily remove it, if I wanted/needed to.
My conjecture is that JD can't sell enough loaders to justify the engineering and logistics costs associated with mfg. and inventory management to make the loader a break even proposition. If you really need a loader, the 1-series would be a better choice for about the same money. Just doesn't make a lot of sense to sell them both.