If you look at the bookies odds when a team gets relegated they are almost certainly favourites to go straight back up, such is the percieved difference in class between the two leagues. Yes Norwich and Swansea are doing very well at the moment. Hull, Blackpool and other similar clubs all done fantastically well to start with but faded 2nd half of the season. This would give your argument merit about the need to improve the squad maybe more than the first 11 because as the season goes on you will need suitable replacements to come in due to injuries and suspensions.
You can see in various cup competitions that Championship sides can more than hold their own against teams from the Prem but these are one off and there is probably more motivation to win a one off game. Looking at the Premier League table, Villa are in 15th and have Darren Bent, and other international class players. You then have QPR who have spent a fair bit of money and now have a "big name" in charge. That leaves the bottom 4 who I think we could match and to be honest if we could finish above the bottom four would be a great season. However as I said at the start, Whoever went down from Wolves, Wigan, Bolton and Blackburn would be strong favourites to go straight back up.
You can see in various cup competitions that Championship sides can more than hold their own against teams from the Prem but these are one off and there is probably more motivation to win a one off game. Looking at the Premier League table, Villa are in 15th and have Darren Bent, and other international class players. You then have QPR who have spent a fair bit of money and now have a "big name" in charge. That leaves the bottom 4 who I think we could match and to be honest if we could finish above the bottom four would be a great season. However as I said at the start, Whoever went down from Wolves, Wigan, Bolton and Blackburn would be strong favourites to go straight back up.