From what I can see, PhotoImpact is aimed more at photo enhancement than vector work. Designer might not be quite what you want as a replacement, but Photo might.
I have Designer. Designer has some features that are amazingly easy to use. Others are not immediately obvious. And if coming from another program as I did (I used Corel Draw a lot, Illustrator less), it took a little while to orient myself to how Designer did the same things.
Also, it took some time getting used to the user interface. Again, that was mostly a matter of learning a new habit. Overall, the program functions are well grouped and easily accessible. There's just a lot of them.
There is a workbook available. It is extensive, and touches on about everything AFAIK.
I haven't got Photo yet. I'm still trying to get a handle on everything Designer does. Designer has the same "layer adjustments" as Photo, allowing all sorts of color effects and tweaks. But Photo has many filters like Photoshop. And a whole bunch of other stuff. Not user unfriendly, just lots and lots of possibilities.