That single point of failure isn't as bad as you might think, because the pressure could be the same on the inside and outside. Cloud-top Venusians wouldn't even need pressurized suits, just breathable air...and protection from the sulfuric acid. And some way to deal with the 200+ mile per hour winds, perhaps by sort of riding them around the planet. I imagine many unmanned missions would precede a manned one, to set up some infrastructure (power generation, oxygen extraction, food crops, etc.) and provide some back up systems.
I'm not sure how they would be able to leave, though. Rocket launches are difficult enough with solid ground and a non-corrosive atmosphere.