Use the middle of your pad and learn to reposition. If the top right corner is most comfy now, move your pad so that place is in the middle of pad. Move your table, chair, monitor etc if need be. Try another chair or table if you feel that's a problem. Get a bigger pad, over double what you use for aim (triple width/height was good for me).
How and in which direction drift happens is personal. Learn to reposition. Learning to aim some pattern without drifting is possible, too.
After playing more the only maps that gave problems were the currently fast/hard maps. The old 4-6* maps that were a problem feel drift free when you can play 7*.
Mappers should just map how they want. If they want to make it easier or more effortless in some aspect they can. The maps are as difficult as they are in differend ways and it doesn't have to match the star rating or pp you get. The perfomance point system's job is to evaluate maps. Mapper's job is not to make sure some map matches the (expected, as in similiar to other maps player has playez of that rating) rating it's given.