I agree completelly, the best option upfront is to keep things as they are. Trez & DP the first line of attack, Palladino & Bojinov the second, with Zalayeta filling up the blanks. Pizzaro is good, he can score a lot of goals, plus he would come for free, still I don't think he's good enough to replace Trezeguet. If anyone's ideal for that part, IMO, it's Klose, Toni also but I prefer Klose.
I think Bojinov can be that, like I said before, he's not a direct replacement for Trez but he can hold his own in a box striker role or a support striker. Palladino and Bojinov could very well be our next lethal duo in the future. The key is to utilise them now and give them their fair chances, something which DD is not doing so far, at least with Bojinov.