Did they make changes to econ? When taking control of an opponents monster with effect #2, I cant change it from defense to attack and then attack my opponent anymore... and, a different opponenet just activated it before battle phase and I wasnt able to put my card back to attack. Has it always been like this or is this new?
You mix 2 effect in your question so I will answer them separately..
1.Did they make changes to econ?.. then attack my opponent anymore...
^I guest you steal it in battle phase and it's in defense position? You can change it in main phase!
2.and, a different opponent just ...is this new?
^I will guess that you special summon it that turn. You can't change position of summoned monster
It might be the case that the opponent has a card that prevents his monsters from being targeted by (magic) card effects. For example, this is what Lord of D does for all dragon type monsters - this cost me a battle once, learned my lesson a hard way :D
No, he can steal it and he can't change its battle position. // I don't think it's about which monster assume he should know that monster/read that it can change battle position or not. This is more than a month anyway. He's long gone :P