I don't think the perfect dink has been built yet, a lot has to do with how you intend to use it. Dinks can be a lot of fun in the marina. We used to leave the big boat at the dock when there was no wind and go exploring in the RIB, lunch and touring. A sailing dink is a blast but has other limitations. Remember that they can also be stolen. Here are some options:
10 foot hypalon RIB with a 15 hp 2 stroke - Ultimate assault boat. fast, stable and fun - will need to be towed and expensive.
fold a boat - can probably store on deck - hassle to assemble and need a small motor.
Fatty knees - sailing fiberglass dink is great for the family to play in and rows well too - doesn't tow well but might fit on deck. Expensive
Tinker - sort of a folding/inflatable RIB with a sail kit - I don't have any personal experience but could be a good compromise.
Roll-up inflatable - easy to store, pain to blow up, small motor. Probably the best option for an ocean crossing cruiser.