I think the new mode is quite nice, but I don't see myself doing the free to play mode much because it doesn't give SPS.
As for the tournament and survival changes, I don't do either of them but I think they are fair changes.
The main advantage of playing in Frontier format is earning cards that can be used in other formats except Survival.
I will play in Frontier because it's fun and because the upgraded foundation cards will be useful in Modern Format.
As for Survival, after the August 5 change, without cooldown, it will be convenient to play because the SPS gains per battle won are similar to those in Modern and there is no Wild Pass ;)