(These answers are from the video in your post)
1) Your video quality is fine as it is in 720p, not really much need for 1080p
2) Your microphone is really quiet, I would suggest bumping up the volume in your editing program or something, but the mic quality is good
3) Yes I would watch some of your future videos!
4) I'm not too sure if I can hear your 'full' voice as I said the audio levels on your microphone are quiet. From what I can hear you could be a bit more 'lively' and 'energetic' (That's mostly how commentators get far) then yes I think your video is good