Well Battledawn and Battlegalaxy are a lot different with players and themes also different,
I remember a time when rules were also change,like 12 ct for razing upgrading ops, or maybe i remember wrong?
Also the thing that is most important here, The Daily Bonus are different for both,Means if you take Bonus on BD and BG you can get 290 tokens per week
But yea it may help the non BG players also plant into BG when they see it on home screen
Like BD players usually dont play BD and vice versa,so if you merge them both ,some extra players might drop by and who knows maybe they like it and bring over teams and friends