I'm in general agreement Bob. I tend to make sugar syrups at 2:1. Adding water is easy if you want less concentration. I don't find it much of a problem particularly in an era when some drinks have 8 to 10 ingredients! Also, it is worth noting that the key in the heating is to heat it past the point where any bacterial or fungal contaminants are killed (usually >65C for at least 5 minutes) and less than the point at which chemical transformations take place (typically past 80C). You want to coax the sugar into super-saturation so heat is helpful. Then let the solution cool slowly back to room temperature before bottling.

Fruit based syrups are different but there is no reason to not make the puree and then add sugar solution if desired/needed (after it cools to room temp). Whether to heat a puree depends on the factors the OP mentioned but also what is needed to assure sterilization. Minimizing contamination assures longer shelf life. Yes, taste matters but so does safety (see news reports on contaminated fruit!).

I also recommend thoroughly washing and drying any container (I use glass generally), then sterilize it (and any lid) in a oven at 70C+ for 10 to 15 minutes. This is similar to what is done with beer before bottling. Adding citric acid and/or a small amount of high proof alcohol also helps preservation after the sugar is made. Keep the container tightly sealed and if there is any fruit puree added, in the refrigerator.