he is the champion though and has been for a while hasn't he? i dont know too much about as i said my vast knowledge about the show from watching one episode whos doing better btw and what matches would you recomend i watch?
In general whoever is champion gets called up (It happened to Seth Rollins and Big E Langston before Bo). But Bo has already debuted on the main roster (Royal Rumble 2013 and RAW after) and got sent back down because he wasn't good enough. Bo is currently holding the belt because it is part of his character. His character is a bad guy that thinks he is a good guy. He thinks the fans love him and cheer him but they actually turn their backs to him (This is true and it is great to see). With time he will turn more fully bad guy.
As for matches to watch:
Any match Rollins has had on NXT, especially during his title run.
The war between the Wyatt family and Adrian Neville, Corey Graves, Kassius Ohno and William Regal.
The gold rush tournament (the tournament to crown the first NXT champ)
the tag team tournament to crown the first tag champs.
Kassius Ohno vs Richie Steamboat series.
Kassius Ohno vs William Regal.
Sami Zayn vs Antonio Cesaro 1 and 2 and the upcoming third match.
Zayn vs Cesaro vs Kruger.
Guys to look out for:
Sami Zayn
Adrian Neville
Leo Kruger
Kassius Ohno
Corey Graves
The Ascension (Rick Victor & Conor O'Brian)
Tyler Breeze
Paige
Emma
Summer Rae