I for one appreciate very much your growing support of the smaller niche communities. I would also urge you to not fully abandon your own community. There is room and a need for what i have been referring to as the Big Box store communities. I would like to see at least a minimum of 25% of your effort remain with your community. When new users come in, especially new users of the consumer type, they are going to initially look to the larger accounts to find content.
If you look at your community and the tags in there verse what is available tag wise on the All Topics trending page you will see a big difference in the variety that are available.
I guess what I am saying is that there is room for one-stop shops and for mom and pop type shops. Variety is what makes life so interesting, and anyone that has lived in a community where their one stop shops closed down they know how devastating that can be to a community once they are established.
By reading your post though I think you are on the right track, my comment is just to point out that there is room for everyone and I hope you do not abandon your own store to much or often.