At the very best, all it is doing is satisfying demands of the ignorant on the inside of the Mainland...
1. We will, no questions asked remove our military threat from Taiwan.
2. At the same time, declare publicly a 10 or 20 year plan to create a Republic and institute democratic reforms, to which they hope Taiwan will participate. (both in the reforms, as well as the Republic)
Those things should become the Party line.
Taiwan would not mind (I don't think) being in an "alliance" with the Mainland. It is the idea that they will be 'ruled by the CCP' that has everyone upset.
An alliance, as far as Taiwan is concerned, would mean that they get to send a regular representative to the Mainland for an official position. Everything else stays the same. Taiwan still has elections, a President, self determination, their own identity, everything.