Anyone already playing BF Evo would be attracted to a C&C titled version. Furthermore, anyone that played the C&C games would certainly be attracted to this.
Could be interesting to see how far you could go with "multi-branding" here.
Use a C&C licence to do additional units/armies for BF Evo so you're only paying a licence fee on those specific units, while using it as a gateway to tempt people into the range as a whole. Then release individual armies based on other licences as well. You pull people in using the licenced stuff and then once you have them hooked you sell them your own non-licenced stuff as well (obviously you can make more money from selling non-licenced products...).
If the licensors object to things being made compatible (such as New Line did with the LotR stuff, which I believe is why GW did LotR as a seperate game and not just a Warhammer addon) you just use the same rules with seperate branding, such as MGP have done with BF Evo and SST Evo - two different product lines but with enough of a shared rules base to make things work together with some tweaking.
You could end up with a ton of "Evo" games that all worked together to allow you to do Modern military vs C&C vs SST vs Alien vs Predator vs BSG vs B5...