Forums are funny things, I approach them by reading the whole thread then re reading the original post.
Your question seems to be Honda or Yamaha. My question is do you do your own oil changes? Plugs? Fuel filter? Gear Oil?
If you do your own maintenance you won't need a dealer unless you have a major breakdown or a scheduled service to keep up your warranty. In that case you seem enamored with the Yamaha so go with that since you'll only be towing your boat to the dealer once a year or less.
If you don't do your own maintenance you'll be taking your boat in 2 or more times a year, if you're a busy household and you've got to get it in for service quick before you leave on a trip then dropping it off before work etc is going to cost you 30 minutes compared to two hours. You don't want to head out on the water knowing you didn't have time to get the plugs done or filter changed(especially if your motor was anything but butter smooth last outing). Then definitely go with the engine from the closest dealer-Honda.
I agree that there's little difference between brands if you're buying brand new. The biggest difference is e-tec vs 4-stroke. And some 4 strokes like the Yamaha F70 are as light or lighter than the comparable e-tec.
About more power, only 1 or 2 Suzuki 90's I've read about(or met in person darrenj

) are hitting 28+mph, 25+ seems to be triple digit horsepower territory. Most of the 70s 75s and 90s are around 20-25mph. The

was advertised as doing 20+knots and in some wording 25mph(IIRC) at the very least 20kts is 22mph. This is squarely in the territory reported by F70 owners. The hull should be able to handle 20kt cruising. F70 at 247lbs is only 20lbs heavier than my old merc 50 so transom weight is a non issue.
As for crossing big wakes thrown up by big boats, I'd get off plane or at least lower my speed if there was that kind of traffic, but that's what any skipper should do(there are horrifying examples of hitting someones wake too fast on youtube including one that was posted here a few years ago).
Insurance with a motor over 50hp is covered in many other threads. Many have been told by their agent that they are covered.
So far I just dont have the dough to upgrade. With my new prop I get to 15kts in a nearly empty

If there's no sudden winfall of cash I'll just try another prop for under $100 and hope for another knot of speed.
Either way I'm sure the thrill of a new motor will leave you smiling not wondering
Willy