The only problem is when you have a storm of injuries.
In normal cases, you can compete in all 3 competetions with 19 players and maintain the 10% training bonus most days without the need of rest packs. Sometimes this becomes harder but most times is bearable. This is how I play without using rest packs most days.
Another problem is that you won't be able to power train fast trainers without buying tokens
.
For me I can't buy tokens due to some reasons.
I just want to try powertraining a fast trainer to 7-8* in my 5* squad and farming is the only way for me to heal excessive injuries and powertrain a player.
Also I'm doing some calculations on the new training bonus system to understand it clearly so without farming ( and I can't buy ) all of these would be impossible.
What do you think ???