To echo what PT said above, I think it's good to schedule maintenance as necessary during the year, and avoid lumping maintenance into the inspection interval. If the inspection really is an inspection, and you're on top of regular maintenance, the number of "gotchas" at annual time should be minimal, and limited to things that would be really hard to identify in a preflight.
If an annual inspection is also a "do all of the maintenance for the year," then it's going to seem high - but should be compared against annual maintenance costs, and not just against annual inspection costs.
The $3500 base annual seems insanely high to me. Here in the midwest, a $1750-1800 base inspection is pretty standard for a J model, and if you have no repairs, you can get away with a total around $2000 to $2500 including consumables.
All of that being said, a new-to-you airplane always has some surprises. Every mechanic focuses on different things, and even if the plane passed its previous annual with flying colors, your new mechanic will find things wrong with it. A 10% annual the first time around seems high but not impossibly high. It's the second 10% annual that would have me looking elsewhere. My advice would be to try a different shop for #3.