I'm not happy at all with the noise of my 7D, and that's of a 2x3 b&w newspaper image!! There is no way I would agree to shoot a wedding w/ the 7D. 6D, without a doubt. You do not have to buy L glass to get quality, especially with a FF. My 85mm F/1.8 is an incredible lens. The 50mm F/1.4 is also great, same with the 35mm F/2.
Go with Canon since you know it and have glass. If you want to switch, go to Nikon not Pentax. I talk with the school photographer for a small, local college because I see him at a lot of events. He was using Pentax, so I asked why. He told me that the head of the multi media department used a Pentax in the film days. The actual photographers hated it. The biggest complaint was much less choices when it comes to lenses compared to Canon/Nikon.
Until he's paying for your equipment, buy what you'd like. Just my opinion. I don't know the fine details. For instance, if he's recommending Pentax because he has a ton of equipment and thought you could use his gear???
You don't even have to go FF to improve from the 7D. Check the thread here regarding the 80D. It would be my next choice if I don't go to FF.