Yes - it would be a good deal warmer. Apparently it was much thicker in Dinosaur days.... back 60 million years or so. It was also much warmer overall and the Ice Ages hadn't started. More oxygen was available for the dinosaurs to breathe, so they didn't always need massive muscles in their diaphragms to operate their lungs.

The additional greenhouse gases would make it warmer.

You're right that increased surface air pressure will reduce the rate of evaporation, but saturation water vapour pressure will increase in proportion to the air pressure, so that (independent of temperature), over time, the amount of water vapour in the atmosphere will double.

Playing what if games like this is ridiculous. There is so much more to consider than just the atmosphere. To have an atmosphere with double the density and pressure like that the world would have to have twice the gravity. And for a world like the earth to have twice the gravity it would need twice the mass. And twice the mass would mean that the world would be much larger. The rotation rate would be much faster to make a 24 hour day because there is much more surface area. Then you need to consider the massive difference in the gravitational effect the moon has on the much larger earth which makes a huge difference in the scheme of things. Then you're talking a whole lot of other unmentioned issues. This is the same crap issues that the AGW fundies have with their incredibly failed computer climate models. They do not account for all the real world variables in their magic climate what if games and the results come out as complete unsubstantiated garbage as has been proven time and time again for the past couple of decades. It's just not that simple so these what if games are meaningless.

This could be the answer to the 'faint young sun paradox' how did Earth have liquid water when the sun was not as strong, as now.

Of course it would be warmer! The extra atmosphere would cause trees to grow faster which would mean they would have really really fat tree rings. Of course, if you keep up on the literature, you would know that fat tree rings are a major cause of global warming.

Q.E.D

how it would ..it may block the sunlight when it is thicker..instead of hot it may just warm

Lets say Earths atmosphere was twice as thick with the same ratio of gases so 78% nitrogen, 21% oxygen, 0.004% CO2 and 0.9% argon. Would Earth be warmer as a result of the thicker atmosphere?