Not a chance in my estimation. They have too many products which compete with each other and they would have to kill or sell off several of them. Adobe's acquisition of GoLive signaled their admission that Pagemill was too flawed (and maligned) for serious website design and their answer was to buy a more serious tool. My impression is that they have realized finally that Macromedia was outpunching them in the internet-creation industry with Dreamweaver, Fireworks and (especially) Flash. Their acquisition of GoLive along with their apparent about-face in their previous dubious strategy of keeping Photoshop web-challenged in order to support ImageReady signals to me that they aren't thinking of merging with Macromedia but, instead are focused on competing with them. I'm sure they would salivate over having products like Director and Flash in their stable but Dreamweaver, Fireworks and Freehand would conflict with their current lineup although they are by-and-large superior to their own offerings. Ain't gonna happen.
My idea of an interesting acquisition would be Macromedia buying Quark. This would seriously bolster there presence in the printing world and give them a leg up on Adobe. Another intriguing possibility would be to see Macromedia and RealNetworks in a merger. That would be more in keeping with Macromedia's webcentric vision and would insinuate them even deeper into the architecture of a media-rich internet. Just something else to chew on.