By the way I'm not just saying this out of naked self interest. I genuinely feel it would benefit him and his career prospects if he stayed with us another 2/3 seasons.
When you have a look on those big clubs' squad,you will find that none of them have a desperate need for a new striker.
Man Utd - Falcao,Van Persie,Rooney
Arsenal - Giroud,Sanogo,Akpom
Chelsea - Costa,Drogba,Remy
Liverpool - Sturridge,Balotelli,Borini
Man City - Agüero,Dzeko,Bony
Therefore they are unlikely to spend big on the striker position,I think Berahino will stay with us at least one more season,it's a good for him and the club.Here he can get numerous chances to play to improve and we can have a 10+ goalscorer