My gas engines are quite reliable with carbs, but electronic ignition. Same with the generator. It's really the ignition system that's the big historical weak point of gas engines, but even by the 80s, things had come a long way. The Mercruiser Thunderbolt ignitions are particularly good, but most of the other electronic setups out there are reliable as well.
As far as torque curve and getting a heavy boat moving, it really depends on the engine choice and how the boat is geared and propped. Something like the basic low output (330 - 350hp) 454s make plenty of torque. A gas boat will need deeper reduction gears than diesels because the gassers are higher revving. And once you need more than somewhere in the 350 - 400 hp per engine range, there just aren't any good, durable choices for gas engines, so it's time for diesels.
Our boat is a little over 27k lbs fully loaded (and 38 feet length on deck), tops out around 25 kts loaded, fast cruise is 17 - 18 kts at 3200 - 3300 RPM. Slow cruise is ~6.5 kts at ~1250 RPM (which is nice and quiet even with poor engine room sound insulation, mostly thanks to huge 2 stage water lift mufflers).
We've got 2.57:1 gears and 22x26 props, so bigger props and lower gears than most of the express style gas boats this size and more on par with the props you'd see on a similar size boat with diesels. As a result, low speed thrust is not an issue. We do about 4.3 kts idling in gear and unless it's very windy, it's fairly rare to need any extra throttle while docking. The boat also has no trouble getting up on plane. Drop the trim tabs a bit, push the throttles forward to approximately the fast cruise position and she just climbs right up and settles in. No plowing and struggling or any drama, just a few seconds of waiting while it finishes accelerating so you can tweak the throttles to where you really wanted them. None of the small gas boat "go WOT and back off when it pops up" stuff, although it will pop up on plane a bit faster if you do.
All of that said, I'd love diesels in this boat, but it would be 90% for the better fuel economy (and corresponding longer range). From an operational perspective (other than fuel economy) and powering the boat appropriately, the gassers are fine.