I would disagree, for confusion you could simply not attack. For staying the active Pokémon, burn would be better. Although that would be after the game.
Very true, apart from the low cost on the basics there's many ways around it now.
Darkrai EX gives your 'mon with dark energy attached free retreat.
Float Stone is a tool which gives free retreat. This is frequently used with Keldeo EX, which has an ability which allows it to become the active Pokémon. Got a paralyzed 'mon? "Rush in, retreat" has been such a common phrase over the year.
Ah, here's the tweest. They rotate sets out so older sets in main competitive play are illegal. So you really are forced to buy new sets if you want to stay competitive:
http://pokegym.net/tower/ shows you the current allowed sets and scans of them all. Click "switch to unlimited" and see all the sets and relive the nostalgia.
We're actually due for a new rotation sometime soon. Speculation is it's going to be Plasma Storm onwards.