If the game would be in 60FPS ...

Well it depends on a few factors in the encoding process, what you do for the video and what matters to you personally. Also the source itself can play a huge factor in how large the file will be when your done, bitrate and such. When it comes to uploading to media sites it's always best to upload as much of the original quality as possible because of it being reduced after processing. So if you want to make a change in the fps, it's up to you but the change will effect the fluidity of the video. Youtube being the exception, it's processing always cuts a video to 30fps not matter what so for now you won't see a 60fps video on there. Personally I've never had a system or PC that could run anything beyond 30fps so to me it's not a big deal. Dreamy Theater 2nd is the first game I've ever played that ran at 60fps so it took quite a bit of time to get used to, F is like water to me ^_^