I noticed this today too, wanted to test out my new Razor v1.1 which is head heavy and stiff compared to my other head light extra flex, I didn't get the extra power I thought I would and defence took a slight beating too, the areas I noticed an improvement was net shots and lifting the shuttle from the net which required no effort whatsoever and they all landed perfectly at the back, some of the problems could have been from the partner I had, he was playing alot of bad shots like clearing to 3/4 of the court from the back while under no pressure and weak backhand returns a foot above the net, I had to compromise by playing different than I'm used to, well I guess I'll get used to it soon, it took me a few weeks to adjust to my Head light s-lite too
Changing rackets, especially ones with large differences in attributes, is very comparable to going from a comfortable shoe you have had for years to a brand new shoe. It's going to take a while to adjust to, one can only 'feel' so much in just a few practice hits. Just give it some time before you write it off.
I agree with others here. It takes time. I went through the same experience. Going from flexible and even-balance (isometric) to stiff and head-heavy (oval), took me a couple of months to get to really get the same kind of results.
How much time is required depends on the variation from your previous racket, and how consciously you try to adapt.
I guess I found it harder to adjust to different flexibility as to different balance. My first rackets from the age of 9 to about 14 were even balanced and extra flex. After that I switched to flex head-heavy ones for enhanced power in singles (played at the regional top-level youth leagues at that time and that required the extra power in singles to keep up with my competition), but I used that one in doubles as well. After that I kept using head-heavy's only until two years ago but made the switch to stiffer ones and that made a lot of difference. As my play improved I was able to have more control using the stiffer ones, and if you use 'm proper you will get more power out of it, but at first you feel like you need to use brute force to get more flex. Later I started to use an even balanced racket for doubles, and that switch was much easier to adjust to than the switch from extra flex to stiff. Now I use even balanced for doubles and head-heavy for singles and can use them both in the same session only needing a few strokes to "get into" the different characteristics.