The nipple is definitely something to check or I would advise you to change it anyway. It’s not a big deal and really costs almost nothing to replace. It’s dangerous if it breaks but don’t get scared that will break out of nothing. Usually you need to apply some pressure on the hose (push it for example) and if it is already corroded it may break. I know this from fist hand when I tried to remove the hose.
I cannot really thing of any particular problems to this specific model. General maintenance items. Engine condition, shaft alignment, standing and running rigging, electric windlass condition, rudder bearings and so on. Get a good surveyor to check everything.
My only complaint is the relatively small diesel tank. It’s enough for 20-24 hours of motoring but could have been better. Of course it depends on how long your passages are. On the other hand the two water tanks (around 340 litres) are perfect for a 36ft boat.
As others have said, the boat is very good for single handled. It’s quite easy to balance it with the appropriate amount of canvas out and sails well in all directions, yes upwind too (well I have the deep keel version- 1.80m with bulb- so cannot say if the 1.53m shallow draft is the same). One thing to remember and I believe it applies to all similar boats, is to respect its “angle limits”. Get a clinometer and make sure that when angles start approaching 20 degrees, then it’s time to reef. You will gain more speed and will be more comfortable.
Good luck with your choice. It will be great to have another Beneteau 361 member in the forum!