You can't ever have too much power.
It's first and foremost, an occasional use tractor. I suppose I'll be using the FEL and root grapple for the most part, followed by cultivator, ground blades, and might skid some logs. A rotary cutter will be a must at some point. I have 170 acres of forest and plan to eventually clear a few acres as a hobby farm and for a food plot for game. I've got just under a mile of dirt road in that's always in need of repair and filling in the ruts. I was hoping my tractor would suit most if not all my needs and last a lifetime with proper care. I figured 30HP was a good number. Would rather not be underpowered in the future, but not sure getting an extra few HP is worth an extra grand or more. That same money could go to the implements I'd need.
Yes you can. If you spend all your money on horsepower and don't have good implements you have too much power. If you spin your wheels despite ballast, you have too much power. If you are running all your regular tasks effectively at well below PTO rpm then you have too much power. If you can pull/run bigger implements than the tractor frame handles easily then you have too much power.
The "more is better" argument is silly. Extra power is wasteful. Balance of power and work is what you want. Figure out what you need to run 90-95% of your tasks efficiently and that is a good target. The other 5-10% of tasks may take a bit longer but in the long run it makes far more sense to operate a tractor close to it's max output 5% of the time than well below it's max 95%.
Maybe money is no issue but for someone cleaning out woods $800 spent on a grapple is way more effective than 5 extra HP. If money is no object then get a bigger frame tractor with bigger loader rather than extra horsepower you will almost never need. I doubt there is noticeable difference in work accomplished in a day between a CK30 and 35 despite the HP difference.
Dealers want to sell more of anything. Ever meet a car or tractor dealer that didn't want to sell more HP? People tend to like more HP than they need because it is any easy sales pitch and they don't think through the downsides or opportunity costs. You won't find many CK30 owners complaining or trading up to a 35. 30 HP is well matched to the CK frame and loader. If you need more think of a bigger frame like a DK.