This really doesn't make a lot of sense, in my opinion.
I have no trouble in driving the ball or hitting a slice approach but when I have to add topspin the racquet feels really sluggish. Because it's really stiff I can't feel myself spinning the ball so Ive got to rely on technique and I refuse to use poly strings to increase spin.
Why, if you're having trouble getting racket head speed, are you using an extended length racket?
Quit using an extended length racket. Try the Pure Drive standard before switching rackets...
An eastern gripper using a Pure Drive Plus is not something you come across everyday. I am just curious, what tension and strings are you using?
I am not sure I understand the remark about feeling the ball to impart spin or not. It sounds like something very similar to the PD's specs with some more flex might be what you're looking for, in which case the Pure Storm is a great choice. The Pure Storm is nearly as powerful as the Pure Drive standard, but flexier with more feel. It is definitely more communicative off the ground. It still serve extremely well.
I think you should try a standard length Pure Drive... If you already have and have the same problem, try the Pure Storm. The AeroPro isn't going to give you much of a difference compared with the PD.
Besides a few of the Wilson recommendations (good post by AndrewD), maybe the KSurge for example, I completely disagree. I don't think any of them are good "substitutes" for a PD. A good substitute is a powerful racket known to be extremely spin-friendly and serve-friendly.