Why stop at 2!? Team training is the new one position training! Why train half of your team when you can train your whole team! Worrying about GS and minutes? TEAM TRAIN. It makes everything easier and that one Friday that somebody pops is even more rewarding and special versus seeing pops every week. That gets boring and predictable!
TEAM TRAINING! WOO!
Sorry,
Preach on, brother!
Got me excited.
Seriously though, 2 position training is definitely viable at any level and I would recommend to a team trying to promote as fast as possible, while still training. Being a U21 coach though I usualy urge(threaten/bribe) people to one position train though :)